I think it's the same old reasons.
People have been short on money for a while now, so in theory, as time goes on more people will just throw in the towel with the football, and crowds will continue to decrease nationwide for some time still.
Looking at tonight:
Brighton got 20,000 - very decent for a club of their size, more than we got against Bristol.
Bristol have always had **** crowds and have been struggling for a couple of seasons now, so more people will be put off as time goes on.
Burnley are struggling and are a small club.
Coventry - nuff said.
Derby got a very decent crowd (for obvious reasons)
Doncaster and Watford - see Bristol and Coventry.
Portsmouth, that is low for them but they aren't much bigger than the clubs above.
West Ham got a very good crowd.
As for us, our ticket prices have gone up, we've had a couple of poor attendances (though no less than 19,000) but the last game we had 24K.
Anyway in short, I'm not shocked by the figures.