Not sure how this helps with Mailonline payments
However to answer your question I would hazzard a guess that more than ever is being submitted to the nationals. Have a look at any Prem games and see how many photographers there are.
Take out the agencies with contracts, like Getty, Action, BPI and you will still see plenty of photographers. Some will be club photographers and some will be on other commissions - i.e. local papers but still lots of images going out on spec.
At Championship games, look at the teams near the top of the league and again plenty of big agencies etc on commissions, and plenty on spec.
Come to Oakwell & The Keepmoat on a wet Tuesday night and not so many.
As some photographers give up others come through to give it a go.
I suspect that it will remain the same for a while yet. But if photographers get fewer and fewer used on spec, then the numbers will decline.
n.b. all my own guess work that is.