From Publishers Weekly
E-book sales jumped 164.4% in 2010, to $441.3 million, at the 14 publishers who report sales to the Association of American Publishers monthly sales program. Sales in December rose almost exactly the same amount, 164.8%, to $49.5 million. Sales in all other trade segments fell in the year with the exception of downloadable audio which had a 38.8% gain to $81.9 million.
Sales in adult hardcover fell by 5.1% at the 17 reporting publishers, while trade paper declined 2% at the 19 houses that report.Mass market paperback sales fell 6.3% at the nine paperback houses; in children's hardcover sales decline 9.5% and paperback 5.7%. Fourteen publishers reported sales to AAP.