From Paid Content:
The Association of American Publishers closes out calendar year 2011 today with a round of new stats on print and digital books. Publishers’ e-book revenues were up 117.3 percent in 2011, with hardcover, paperback and mass market sales declining sharply and affected in part by Borders’ closing.
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It was a bad year for mass market paperbacks, down 35.9 percent over 2010. Publishers’ revenues from e-books jumped 117 percent for the year, with the heavier growth in the first part of the year and some slowing into December.
Link to the rest, with charts, at Paid Content