Aptara, which enriches content for digital distribution, has just completed its fourth annual E-book Survey for Publishers, this year done in cooperation with PW. The new results show a number of notable changes, reflecting the growing influence of digital in the book industry; most significantly, there was a 100% year-over-year increase in the number of publishers who reported drawing more than 10% of their annual revenue from e-books.

Dev Ganesan Aptara president and CEO, says, “The ‘more than 10% of revenue’ metric has been used by industry analysts to indicate when e-books cross the threshold and become big business for publishers. With more than a third of e-book publishers there, I’d say it’s official.”

Among other statistics of note in this year’s survey is that four out of five publishers are now producing e-books. And although most houses are producing (and releasing) print and digital copies of titles simultaneously, 11% of publishers reported focusing on e-only titles.