Sales of e-books more than doubled from 2010 to 2011, according to a survey of nearly 2,000 publishers by the Book Industry Study Group, a research organization, and the Association of American Publishers.

E-books jumped from 6% of the market to 15 % and e-revenue for new adult fiction is now higher than the revenue for hardcovers, notes the “Associated Press” ( Sales for books overall dropped 2.5% to $27.2 billion and 12.6% at physical stores, thanks in part to the fall of the Borders superstore chain, the article adds.