Darllenwch y dudalen hon yn Gymraeg

Today marks a significant milestone in the release of 2021 Census data. On 28 June, the Office for National Statistics (ONS) published the first results from the 2021 Census for Wales. These first results include rounded population estimates for local authorities in Wales, by sex and five-year age groups. The release also includes household estimates, and information about population density.

On Census Day, 21 March 2021, the size of the usual resident population in Wales was estimated to be 3,107,500, the largest population ever recorded through a census in Wales. This represents population growth of around 1.4% since the last census in 2011, or an increase of around 44,000 people. Meanwhile, the population in England is estimated to have grown by around 6.6% during the same period, by almost 3.5 million (more than the size of the population in Wales!).

The data published today show signs that population growth in Wales is slowing down. Between the censuses in 2001 and 2011, the population grew by around 5.5%, or just over 160,000. The rate of population growth is also estimated to have slowed down in England, but to a lesser extent than in Wales. In England, population growth was 7.9% between 2001 and 2011, slowing to 6.6% between 2011 and 2021.  

While the population is estimated to have grown in most local authorities in Wales, there are several local authorities estimated to have lower populations in 2021 than in 2011. The greatest rates of population decrease since 2011 were in Ceredigion (5.8%), Blaenau Gwent (4.2%) and Gwynedd (3.7%). On the other hand, population growth is estimated to have been highest in local authorities in south-east Wales. The local authorities that had the highest rates of population increase since 2011 were Newport (9.5%), Cardiff (4.7%), and Bridgend (4.5%).

So, what’s behind these changes in population growth? Data from the ONS tell us that from April 2011 until the end of March 2021, there were 321,000 live births and 332,000 deaths registered in Wales. This represents a decrease of approximately 11,000 usual residents overall. The estimated population growth since 2011 is because of positive net migration (approximately 55,000 usual residents) into Wales. This includes both international migration and moves within the UK.

How does this compare with other estimates of the population?

The census achieved a fantastic response rate and the ONS undertook comprehensive quality assurance, including involving local authorities for the first time. But some of the data published today may still come as a surprise to some people. The latest mid-year estimates of the population for Wales published by the ONS suggested there had been population growth in each local authority in Wales since the 2011 Census, other than in Ceredigion.

There will be a number of reasons why the census estimates look different. One reason is that population change in certain areas may reflect how the pandemic affected people’s choice of usual residence on Census Day. These changes might have been temporary for some and more long-lasting for others. It is also not clear how exiting the European Union has affected population change in Wales and across the UK.

It is also important to remember that the latest mid-year estimates from the ONS are based on the 2011 Census. The estimates become increasingly more uncertain over time as we move further away from the 2011 Census baseline. The 2021 Census has therefore provided the opportunity for us to update our understanding of the population as it was in March 2021.

Later this year the ONS is planning to publish more analysis comparing the Census population estimates with other sources of population data. This will include comparisons with the latest mid-year estimates and the more experimental admin-based population estimates. The ONS will also publish more information on what the Census results mean for updating the existing series of population and migration statistics.

This analysis will be especially important as the ONS researches a new approach to producing population estimates. The ONS aims to deliver more frequent and timely population statistics, which also address the challenges of estimating the population from one census to the next. I look forward to working with the ONS on this, as well as working together to better understand some of the differences we see between the 2021 Census estimates and other sources of population data for Wales.

What’s coming next from the 2021 Census?

The ONS is planning to publish topic summaries of 2021 Census data from October this year. This will include information on new topics collected such as sexual orientation, gender identity and veterans of the UK Armed Forces, as well as information about ethnicity and identity, health, housing and employment, and how many people are able to speak Welsh.

The wealth of data that will be available from the 2021 Census will give us a detailed picture of what life was like in Wales in the midst of a global pandemic, and will be used for years to come for planning and delivering local services. The data will be used to help the Welsh Government and others to make decisions at the national and local level in order to improve our social, cultural, environmental, and economic well-being.

None of this would have been possible without the willingness of the Welsh public to take part in the census, and the brilliant work of our colleagues in the ONS, supported by local government and community organisations across Wales. Diolch bawb!

Stephanie Howarth
Chief Statistician