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

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)

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 3: Population pyramid - 1926 Census

Figure 4: Population pyramid - Census 2021

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)