From what I have seen at my own team (Milton Keynes Lightning) there are about 2,000 people per week and when there is a free public skate after the games there will be around 150-200 who touch the Ice, some more capable than others.
There are probably more who can but who just don't participate or are too young to not skate in mixed groups that big.
In terms.of playing, MK has a fairly strong youth hockey program for boys and girls starting from U8's up to U18, then a good amount of Rec League/Beer League teams then two teams in the NIHL league system (Lightning and MK Thunder) so a fair amount of match goers will have played.
In areas where youth hockey is bigger still like Nottingham, Cardiff, Swindon, London, Hull, Scotland, Sheffield those percentages would probably be bigger still (especially Sheffield).