The AAP have release the official numbers for September ebook sales
E-book sales continue to grow, with a 158.1 percent increase over September 2009
($39.9 million); year-to-date E-book sales are up 188.4 percent.
It's good that they're promoting the fact that sales are up over last year, but sales have still hit a plateau. Remember, the reported figures for August and July were also around $40m. We're not seeing the same growth as last year; it's time everyone stopped kidding themselves.
P.S. There are 2 things you need to keep in mind with these figures. Ebook apps aren't included (I asked), and most indies aren't included. This plateau in sales mainly affects the established major publishers.
P.P.S. Some time back I made a prediction that ebook sales wouldn't track with paper book sales. This months suggests (but doesn't prove) that I'm right. The book market is down, in general, but ebooks sales remained flat.