I do now have the answer…
BUT, frustratingly, it turns out that rather than just being a football question, it was a work/football question. I work in real estate…
xxnick1975 was getting as close as any of us were likely to get by spotting that all of the teams had won the top division.
The numbers actually represented the % return on the UK real estate market in the years that each team won the top division.
I spent ages looking at squad sizes, year each club was formed and even asked google Bard for an answer (it seems were a long way off AI solving anything like this!).
Sorry!!