The report is called 2013 U.S. Book Consumer Demographics and Buying Behaviors Annual Review, and it shows that 44% of books (both analog and digital) purchased in the US were bought online. This is up slightly from last year, when only 39% of books were bought online.
I only have access to the press release so I don't have all the details in the report, but that press release does include a few driblets of information. For example, the PR mentions that women increased their lead over men in book buying, accounting for 58% of overall book spending in 2012, up from 55 percent in 2011.
eBooks also made up a larger share of the market in 2012, accounting for 11% of spending in 2012, compared to 7% in 2011. But that's not the best part. Bowker is also reporting that B&N isn't selling as many ebooks as they used to. In 2011 an estimated 6% of their revenue came from ebooks, and Bowker is now reporting that ebooks now account for only 4%.
Of course, that is just an estimate based on a limited survey of a few thousand consumers
, but that last detail is supported by B&N's own quarterly reports (which show a drop in digital revenue).