This is a summary of the article that I have read for forum members, this article from a newspaper the standard, the article confims what others have posted in this section about the popularity of electronic books:
Electronic books have more than doubbled in popularity during 2011 outselling hardcover adult fiction books. Electronic book sales jumped 15% in 2011 from 6% in 2010 to 21% according to the Association of American Publishers and the Book Industry Study. Overall the slaes of books in the US declined 2.5% to $27.2 billion. Still the majority of publishers revenues came from print books (my own comments here) sales of electronic books should comprise a simple majority by mid 2013.