A quick check on your official website
Att 18706 in Sept against Fulham
Att 19252 in Dec against Derby
Att 19529 in Dec against Wolves
That's just for starters and remember those teams are nearer to you than us, so you can't blame fewer away fans.
They couldn't all fit into the athletics stadium. There were 2K season ticket holders there. Don't assume the 8K that went to Withdean were the same 8K every week. You wouldn't want to take the elderly and young to a match where you were completely open to the elements all the time.
Sod it...