Report by ITV Wales National Correspondent Rob Osborne
The UK National Archives has published the 1921 census for England and Wales, as the 100-year rule, which ensures records are closed to the public for 100 years, has ended.
Taken on 19 June 1921, the census is a survey of 38 million people living in Wales and England during a period of economic turmoil between two world wars and recovering from a global pandemic.
It has taken a team of hundreds of Findmypast conservators, technicians and transcribers almost three years to conserve and digitise more than 30,000 bound volumes of original documents, stored on 1.6 linear kilometres of shelving, ahead of publication today.Martin Johnes is a Professor of modern history at Swansea University. He believes the census is "much more than a pile of names and occupations".
He said: "At one level, it counts people. It tells us how many people speak a language, it tells us how many people are in a country and that's really important for planning policies - how can you know how many schools you need if you don't know how many people are in your local area?
"That kind of data is released very quickly, but the personal data - the individual returns that people make - isn't released for one hundred years.
"And that's really important to individuals, you can find out about your grandmother or your great grandmother, you can find out about your family history, you can look up who was living in your house.
"But it's also important to historians as well because they can see what a society was like, what kind of jobs people had, what they were doing, and also change over time, so for example, you could look at a family within the census and see how the language they spoke changes over time."
Professor Johnes stressed how exciting the census is for historians. He said: "Archives and records is what it's all about. Having access to new ones, that's what we dream about, that's what we get excited about.
"This is an exciting moment, but not just for historians, for anybody, because this history belongs to us all."
You can access the 1920 census online but you will have to pay on entry. The National Library of Wales in Aberystwyth is one of the few locations in the UK where you can get it for free.
Beryl Evans, Family Historian at The National Library of Wales, said that although many people use the census to look at their family history, there's a lot of people searching "the history of their houses and of course social history."
A century-old census is released once a decade, though the next one won't be available until January 2051.
Beryl said: "The 1931 census was taken but unfortunately it got destroyed by fire and the 1941 census was cancelled due to World War Two, so the next one will be the 1951 census released in January 2051 - hopefully I'll be alive to see it."