Executive summary
The Northern Ireland Statistics and Research Agency (NISRA) today (24 May 2022 at 9.30am) released the first results from Census 2021. The key points from this release are:
- the population on census day, 21 March 2021, was 1,903,100 – the highest ever recorded
- since 2011, the population has increased by 92,200 or 5%
- since 2011, the population aged 65 and over has seen the largest increase of 62,800 or 24%
- on census day 2021, there were 768,900 households with usual residents – again, the highest ever recorded
- since 2011, the number of households has increased by 65,600 or 9%
- over the last decade, the number of households increased by 9% and the population increased by 5%
- the average household size has reduced from 2.54 in 2011 to 2.44 in 2021
1. Introduction
The collection of returns for Census 2021 is discussed in the Census 2021 operational report. Census 2021 was successfully delivered with a high level of self-completion and public engagement. The levels of response were the highest since the 1991 Census in terms of percentages and the highest ever in terms of numbers. Furthermore, Census 2021 was a predominantly online census with over 80% of returns made online. These factors, when combined, point to Census 2021 providing high quality statistics which will be vital for future planning.
The Census 2021 online and paper collection platforms closed in summer 2021. The data collected has been processed, coded, and quality checked to create the initial results presented here.
Census 2021 gives a detailed picture of Northern Ireland on census day – 21 March 2021. It was important to understand our population during the Covid-19 pandemic and with the record levels of completion and extensive online collection we have collected extremely high quality data.
Clearly the pandemic has affected and continues to affect our population in a variety of ways (for example, health impacts, working from home) and in future census reports, NISRA will draw out some of these issues further. In addition, data sources such as the Coronavirus Infection Survey coupled with Census data will help to meet the needs of users in looking to the future.
The remainder of this report outlines the results and key messages from the first release of Census 2021 statistics.
2. Census day population
The usually resident population of Northern Ireland on census day, 21 March 2021, was 1,903,100 people. The population comprised 967,000 females and 936,200 males, which means that for every 100 women there were 97 men.
The vast majority (99%) of the population (1,876,800 people) live in 768,900 private households. The remaining 1% of the population (26,300 people) live in communal establishments (for example, Nursing Homes, Halls of Residence, etc.).
On census day, there were 365,200 children (aged 0 to 14) or 19% of the population. Those aged 65 and over represented 17% (326,500) of the population. The remaining 64% of the population, or 1,211,400 people, were aged between 15 and 64 years.
Table 1: Census 2021 population by age band
| Age band | 2021 Census population | Percentage of population |
|---|---|---|
| 0-14 | 365,200 | 19% |
| 15-64 | 1,211,400 | 64% |
| 15-39 | 594,300 | 31% |
| 40-64 | 617,100 | 32% |
| 65+ | 326,500 | 17% |
| 65-84 | 287,200 | 15% |
| 85+ | 39,400 | 2% |
| All ages | 1,903,100 | 100% |
Note: Figures may not sum due to rounding
Figure 1 develops this further to show the Census 2021 population broken down by five year age bands. The graph shows that the age bands 50 to 54 and 55 to 59 are the most populous, each at around 130,000 people. The graph also shows the standard fall-off in population numbers in the older age bands due to the impacts of mortality. A fuller description of the age distribution is given in sections 3.2 to 3.4.
Figure 1: Census 2021 population by five year age band
3. Population change over time
This report will consider the changes in the Northern Ireland population across two time periods. The first considers long term trends from either the 1851 or 1926 censuses to the 2021 census, and the second outlines more recent trends between the 2011 and 2021 censuses.
3.1. Total population – long term change
The Census 2021 population of 1,903,100 represents the highest population ever recorded in Northern Ireland. The 1841 pre-famine period peak for Northern Ireland was 1,649,000, after which there was a long period of decline in population until it reached a “modern” low of 1,236,100 in the 1891 Census. By the 1901 Census the population had stabilised at 1,237,000.
In the twentieth century, successive censuses all show population growth, albeit at differing rates of increase. This has continued into Census 2021. The overall trend is shown in Table 2 and Figure 2.
In overall terms, the population has increased by over 50% since the first census taken under Northern Ireland law in 1926. The more recent (1961 onwards) rate of growth has on average been consistent, apart from the 1971-1981 inter-censal period. The 1971-81 period coincides with the start of “The Troubles” which had a marked impact on the population.
In the decade since the 2011 Census, the population has increased by 92,200 people; an annualised equivalent percentage rate of growth of 0.50%. This represents a reduction in growth over the previous 2001-2011 period, however the recent period of growth is still the fourth highest in any inter-censal period. (Annualised percentage growth is the rate of growth between census periods, considered as if change has been on an annual, uniform basis. This allows better comparison of overall growth as the time periods between censuses varies.)
Table 2: Census year population estimates (1851-2021) with annualised percentage growth
| Year | Population | Annualised percentage growth |
|---|---|---|
| 1851 | 1,440,800 | NA |
| 1861 | 1,396,200 | -0.31% |
| 1871 | 1,359,200 | -0.27% |
| 1881 | 1,304,800 | -0.41% |
| 1891 | 1,236,100 | -0.54% |
| 1901 | 1,237,000 | 0.01% |
| 1911 | 1,250,500 | 0.11% |
| 1926 | 1,256,600 | 0.03% |
| 1937 | 1,279,700 | 0.17% |
| 1951 | 1,370,900 | 0.49% |
| 1961 | 1,425,000 | 0.39% |
| 1966 | 1,484,800 | 0.82% |
| 1971 | 1,536,100 | 0.68% |
| 1981 | 1,543,000 | 0.04% |
| 1991 | 1,607,300 | 0.41% |
| 2001 | 1,685,300 | 0.47% |
| 2011 | 1,810,900 | 0.72% |
| 2021 | 1,903,100 | 0.50% |
Figure 2: Census year population estimates (1851-2021)
Note: The base for the y-axis is 1 million people
3.2. Age band – long term change
Table 3 shows the population by age band from the 1926 and 2021 censuses as well as the level of change.
Table 3: Census year population estimates by age band (1926 and 2021)
| Age band | 1926 Census population | 2021 Census population | Percentage change |
|---|---|---|---|
| 0-14 | 364,400 | 365,200 | 0% |
| 15-64 | 790,300 | 1,211,400 | 53% |
| 15-39 | 486,800 | 594,300 | 22% |
| 40-64 | 303,600 | 617,100 | 103% |
| 65+ | 101,800 | 326,500 | 221% |
| 65-84 | 97,000 | 287,100 | 196% |
| 85+ | 4,800 | 39,400 | 721% |
| All ages | 1,256,600 | 1,903,100 | 51% |
In overall terms, the population has grown by 51% from 1926 to 2021. However this growth is not uniform across all age bands. The absolute number of children (0 to 14) has not changed from 1926. The number of people aged 15 to 64 has increased from 790,300 in 1926 to 1,211,400 in 2021. Within this working age band, there has been a larger increase in the older 40 to 64 age band which has increased by around 100%, from 303,600 in 1926 to 617,100 in 2021.
The population in the 65 and over age band shows an even starker change. This age band has increased from 101,800 people in 1926 to 326,500 in 2021. Indeed, while the absolute number of the most elderly people (those aged 85 and over) is small, this group has increased from 4,800 in 1926 to 39,400 in 2021 – a remarkable rise.
All of this points to an ageing population. There are a number of ways to consider this, one of which is drawn out in two population pyramids (Figures 3 and 4) for 1926 and 2021.
Figure 3: Population pyramid - 1926 Census
Figure 4: Population pyramid - Census 2021
The pyramids show differences in population structure over time. Historically there was a marked “base” with larger numbers of children and smaller numbers of people in middle/older ages. By 2021 this had changed to a more rectangular population structure.
3.3. Age band structure – long term change
An alternative way to look at long term change, is to assess over time the percentage change of age bands within the overall population.
Figure 5 shows the percentage of the population for two age bands (0 to 14 and 65 and over) from 1851 to 2021. Considering these groups allows for the examination of population ageing from 1851 to 2021 – the data are provided in the excel tables published today.
Figure 5: Census year population percentage by selected age band (1851-2021)
The graphs show a remarkable change. The percentage of children (0 to 14) has fallen from around 36% in 1851 to 19% in 2021. In contrast, the percentage of older people (aged 65 and over) has risen from 5% in 1851 to 17% in 2021. As the post war “baby-boom” generation continues to age, this will drive further ageing. Indeed, it is expected that within the next ten years, there will be more people aged 65 and over than children aged 0 to 14 years.
An alternative assessment is to look at the relative size of the groups across the whole population. Figure 6 shows this for the period 1926 to 2021.
Figure 6: Census year population percentages by age band (1926-2021)
The number of older, working age adults (aged 40 to 64) represented 24% of the population in 1926. By 2021, this group represented 32% of the population.
For those aged 85 and over, there was a small drop in absolute numbers between the 1926 and 1937 censuses from 4,800 to 4,200. Since then, the number of those aged 85 and over has increased with every census, rising to 39,400 people in 2021. This analysis leads on to considering the concept of dependency and the “dependency ratio”.
3.4. Dependency ratio – long term change
The dependency ratio is a measure of the relationship between the number of “dependents” and the number in the “working” population. This is useful when assessing demographic change and can highlight trends in the need for social support.
Two dependency ratios are considered. The first is the number of children (aged 0 to 14) for every 100 people of working age (aged 15 to 64). The second ratio is the number of people aged 65 and over for every 100 people of working age. Given that most children and people aged 65 and over are economically inactive, these ratios can be interpreted as the number of people ‘dependent’ on the working population. A fuller description for measuring dependency ratio can be found online.
Figure 7 shows the trend from 1926 to 2021 in dependency ratios. The children’s dependency ratio has fallen from 46 children per 100 people of working age (1926) to 30 children per 100 people of working age (2021), with the decline most marked since 1971. Conversely, the number of people aged 65 and over for every 100 people of working age has risen from 13 (1926) to 27 (2021) – with the scale of the recent increase being clear in the graph below.
Figure 7: Number of children (0 to 14) and older people (65 and over) per 100 people of working age (15 to 64)
3.5. Age band comparison – short term change
Focussing on the decade from the 2011 Census to Census 2021, the population has increased from 1,810,900 to 1,903,100, an increase of 92,200 (5%). Again this change is not uniform across all age bands. These changes can be seen in Figure 8.
Figure 8: Census year population estimates by age band (2011 and 2021)
The largest broad age bands in the population are the two working age bands (15 to 39 and 40 to 64). These have increased by 19,000 persons in total or by 2%. However, as Figure 8 shows, the number of people aged 15 to 39 decreased by 4%, while the number of people aged 40 to 64 increased by 8%.
The population aged 65 and over (combining the 65 to 84 and 85 and over categories) has increased by 24%. Within this group, the number of people aged 65 to 84 increased by 24%. The largest percentage change in population has been among those aged 85 and over – which rose from 31,400 to 39,400, an increase of 25%.
Figure 8 shows that the number of children (aged 0 to 14) increased from 354,700 to 365,200, an increase of 3%. This pattern is disaggregated in Figure 9.
Figure 9: Census year population estimates of children (2011 and 2021)
Note: The base for the y-axis is 80,000 children
Figure 9 shows that the number of children aged 5 to 9 and 10 to 14 have both increased between 2011 and 2021, by 12% and 7% respectively. In contrast the number of young children aged 0 to 4 has decreased by 9% (from 124,400 to 113,800).
This fall is in line with the latest figures on birth registrations from the General Register Office. In total, there have been 239,500 births registered in Northern Ireland over the decade. However the number of births registered has fallen in recent years, reaching a low of 21,500 births registered in 2020, down from 25,500 births registered in 2011. See the monthly births publication on the NISRA website.
3.6. Sex composition – long term change
The Census 2021 population comprised of 967,000 females and 936,200 males, 51% and 49% respectively. This means that for every 100 women in the population there are 97 men.
The number of males per 100 females over time can be seen in historical tables released today. The long term trend from this data is shown in Figure 10.
Figure 10: Males per 100 females over time (1851-2021)
It can be seen that the number has been gradually increasing from a low of 90.8 males per 100 females in 1881 to 96.8 in 2021. This trend has been impacted by two factors. First, during “The Troubles” a significant number of UK Armed Forces were based in Northern Ireland. These service personnel were predominantly male and usually resident in Northern Ireland. This accounts for a large part of the increase seen in the 1971 and 1981 census years shown.
The second impact is seen in the recent increase from 2001. This change is a consequence of reductions in early mortality in males. Historically, older males have passed away in larger numbers relatively earlier in their lives compared to their female counterparts; in recent years this difference has reduced.
4. Northern Ireland population within the UK and island of Ireland
This section compares the structure of the Northern Ireland population within the UK and the island of Ireland.
4.1. Northern Ireland within the United Kingdom
A census was held in England and Wales in 2021 and a 2022 census is currently ongoing in Scotland. Census results for the UK as a whole will therefore not be available until 2023. Given this, Census 2021 results for Northern Ireland are compared to the 2021 population projections for Great Britain in Table 4.
Table 4: 2021 Census/population projections for the UK, by country
| Country | 2021 population | Proportion of United Kingdom |
|---|---|---|
| England | 56,799,600 | 84.30% |
| Scotland | 5,469,400 | 8.10% |
| Wales | 3,180,100 | 4.70% |
| Northern Ireland | 1,903,100 | 2.80% |
| United Kingdom | 67,352,200 | 100.00% |
4.2. Northern Ireland within the island of Ireland
A 2022 census is ongoing in the Republic of Ireland. However the Central Statistics Office, Ireland produce annual population estimates for the Republic of Ireland. Table 5 compares the Census 2021 population results for Northern Ireland with the 2021 population estimates for the Republic of Ireland.
Table 5: 2021 Census/population estimates for the island of Ireland, by country
| Country | 2021 population | Proportion of island of Ireland |
|---|---|---|
| Republic of Ireland | 5,011,500 | 72.50% |
| Northern Ireland | 1,903,100 | 27.50% |
| Island of Ireland | 6,914,600 | 100.00% |
The population statistics from Tables 4 and 5 are shown in map form in Figure 11.
Figure 11: Map of the UK and the Republic of Ireland with 2021 population totals
4.3. Age band – Northern Ireland within the UK and island of Ireland
Table 6: Population of the UK and the Republic of Ireland, by percentage age band
| Country | Population | 0-14 | 15-64 | 65+ |
|---|---|---|---|---|
| England | 56,799,600 | 17.90% | 63.40% | 18.70% |
| Scotland | 5,469,400 | 15.60% | 64.80% | 19.60% |
| Wales | 3,180,100 | 16.40% | 62.30% | 21.30% |
| Northern Ireland | 1,903,100 | 19.20% | 63.70% | 17.20% |
| Republic of Ireland | 5,011,500 | 19.90% | 65.30% | 14.80% |
Figure 12 shows that Northern Ireland lies between the other UK countries and the Republic of Ireland in terms of proportions of children (0 to 14) and older adults (65 and over). For children, the rest of the UK has a lower proportion of children while the Republic of Ireland has a higher proportion. For older adults (65 and over), the rest of the UK has a higher proportion and the Republic of Ireland has a lower proportion.
Figure 12: Proportion of the UK and the Republic of Ireland population, by age band
5. Household estimate changes over time
Census 2021 counted 768,900 households with usual residents. This is an increase of 9% (65,600) from the 703,300 households recorded in the 2011 Census. The overall trend in households is shown in Table 7 and Figure 13.
Table 7: Census year households estimates (1851-2021)
| Year | Households | Annualised percentage growth |
|---|---|---|
| 1851 | 274,700 | NA |
| 1861 | 277,600 | 0.10% |
| 1871 | 275,500 | -0.07% |
| 1881 | 263,300 | -0.45% |
| 1891 | 259,300 | -0.16% |
| 1901 | 265,200 | 0.23% |
| 1911 | 269,100 | 0.15% |
| 1926 | 262,900 | -0.15% |
| 1937 | 296,300 | 1.09% |
| 1951 | 329,100 | 0.75% |
| 1961 | 372,800 | 1.26% |
| 1966 | 399,100 | 1.38% |
| 1971 | 427,400 | 1.38% |
| 1981 | 462,300 | 0.79% |
| 1991 | 530,400 | 1.38% |
| 2001 | 626,700 | 1.68% |
| 2011 | 703,300 | 1.16% |
| 2021 | 768,900 | 0.90% |
Table 7 shows that there have never been more households in Northern Ireland. The number of households has grown continuously since the 1926 Census. Considering the annualised percentage growth, it can be seen that the rate of growth has reduced from a peak of 1.68% per year in the period from 1991 to 2001, to 0.90% per year in the period from 2011 to 2021.
Figure 13: Census year households estimates (1851-2021)
5.1. Average household size
In addition to the overall population and the overall number of households in Northern Ireland, it is also important to consider the average household size. This combines population and households to give the average number of people in each household.
As noted previously, the population grew by 5% from 2011 to 2021 while the number of households grew by 9% over the same time period, meaning that the average household size has fallen from 2.54 in 2011 to 2.44 in 2021.
This downward trend is also evident in the historical figures, shown in Figure 14. In 1851 the average household size was around 5 persons per household. By 2021, the figure had fallen markedly to less than half the average household size of 1851.
Figure 14: Census year average household size (1851-2021)
Average household size is influenced by population ageing. Over the last few decades, older cohorts (people aged 65 and over) are surviving longer in life and this in turn drives household growth as these cohorts retain occupancy of their household. This will be examined further in future census releases on family demography.
Reductions in the average household size will have implications for the planning and funding of public services and is a key finding from the initial results from Census 2021.
6. Further information
This first release of results from Census 2021 will be followed by a number of future releases. Further information about these are set out in the Census 2021 outputs prospectus.
A number of papers on the Census 2021 have also been published on the NISRA website today. These include:
- Census 2021 population and household estimates for Northern Ireland quality assurance report
- Census 2021 methodology overview
- Census 2021 population and household estimates for Northern Ireland report (PDF, 226 KB), laid before the Assembly
Information on Census 2021 in England and Wales is available from the Office for National Statistics website and information on Census 2022 in Scotland is available from the National Records of Scotland website. United Kingdom census statistics will be produced when estimates are available for all countries. The Scotland and Northern Ireland Registrars General and the National Statistician released a “Statement of Agreement” on the conduct of the 2021 round of UK censuses. As part of this there is a UK census data group. Anyone wishing to contribute to work on UK census statistics should get in touch via email census@nisra.gov.uk
Following the 2011 Censuses, NISRA and Central Statistics Office (CSO), Ireland, published a joint Ireland and Northern Ireland 2011 census report. In 2018 an agreement between the CSO Director General and the Registrar General was signed on Census 2021. Whilst the census in the Republic of Ireland was held in 2022, officials are planning to produce a joint report on statistics from the 2021/22 censuses. Anyone wishing to contribute to work on the Ireland – Northern Ireland census statistics report should get in touch via email census@nisra.gov.uk
7. References
The references considered in this report:
- Census 2021 operational report
- Published tables (Excel, 228 KB)
- Baby-boom information
- Measuring dependency ratio
- NISRA - monthly births publication
- Population projections for Great Britain
- Population estimates for the Republic of Ireland
- Census 2021 outputs prospectus
- Census 2021 population and household estimates for Northern Ireland quality assurance report
- Census 2021 methodology overview
- Census 2021 population and household estimates for Northern Ireland report (PDF, 226 KB)
- Office for National Statistics website
- National Records of Scotland website
- Ireland and Northern Ireland 2011 census report
8. Background notes
The data for this release on population and household estimates is available on the NISRA website at www.nisra.gov.uk/census2021
The mid-year estimates are an annual series of population estimates based on the most recent census. Up to 1971, the census statistics are the mid-year estimates for the relevant census year. The mid-year estimates for 1981 and 1991 differ from the census statistics as they allow for people not counted in the census. Therefore the information presented in this report for 1981 and 1991 are the mid-year estimates. From the 2001 Census, small adjustments for under-enumeration are built into the census estimates. As such the 2001, 2011 and 2021 Census statistics are shown in this report – as they represent the full population.
The figures in this report for the rest of the UK and the Republic of Ireland represent the most recent population projections or estimates available for 2021. These figures will be updated by the relevant statistical authorities in due course.
The numbers presented in this report have been rounded to the nearest 100 persons to protect confidentiality. Census 2021 data will be subjected to further disclosure control processes to protect respondent confidentiality. The baseline numbers in future releases may be marginally different due to the impact of removing rounding and any further statistical processes applied for confidentiality protection.
Census Office welcomes feedback from users on the content, format and relevance of this release. Please send feedback to the email address below.
Further information can be obtained from NISRA Customer Services at:
Telephone: 028 9025 5156
Email: census@nisra.gov.uk
Responsible Statistician: Dr David Marshall