For the trade, where we focus our reporting and analysis, they estimate sales of $12.517 billion for 2011, down slightly from estimated sales of $12.59 billion in 2010. (This is our first point of divergence with other accounts. BookStats actually includes religious book sales in their "trade" reporting, so the totals you will see elsewhere will tell you that "trade" sales were up a tiny bit rather than down a little, at $13.97 billion, an increase of $70 million or 0.5 percent over 2010--because religious sales did grow. Our trade numbers set aside the religious publishing data. This is consistent with how the AAP now separately reports monthly data, in which religious books are a category of their own, separate from trade books.)
eBooks vaulted to the largest-selling format for adult fiction, comprising 31 percent of dollar sales. Adult fiction ebooks went from $585 million in 2010 to $1.27 billion in 2011. All trade ebooks as estimated by BookStats accounted for $1.97 billion (by our definition, without religious ebooks), compared to $838 million in 2010, an increase of 135 percent--or $2.074 billion (BookStats' definition, including religious books), compared to $878 million in 2010. eBooks accounted for almost 16 percent of all trade dollar sales (or almost 15 percent by their definition). eBook unit sales increased far more, up 210 percent, to an estimated 388 million units.
And paidContent's look at the results
Ebook sales way up in 2011; overall trade book sales roughly flat
And The New York TImes has a look at the stats - Survey Shows Growing Strength of E-Books
While at Bloomberg - U.S. Book Sales Declined in 2011 Despite Rise in E-Books
While at Galley Cat - eBooks Now ‘Dominant Single Format’ in Adult Fiction Sales