Back in 2004-5 the annual turnover of the jazz sector of the UK music industry was estimated to have reached £86.77m. There were at least 45,000 jazz performances a year in the UK, ranging from sessions in pubs to concert hall and international festival events. The core audience was about 500,000 people.
Although that’s a decade ago the 2006 report detailing the value of jazz in Britain has now been posted on the web at https://www.academia.edu/9709384/The_Value_of_Jazz_in_Britain_by_Mykaelll_Riley_and_Dave_Laing
THE VALUE OF JAZZ IN BRITAIN. Report commissioned by Jazz Services Ltd from Mykaell Riley and Dave Laing of the University of Westminster, with additional contributions from Catherine Loveday and Norton York. (Dceember 2006)