Bowker, which keeps track of such things, announced at the Frankfurt Book Fair this week that the number of self-published titles went up 59% last year versus the year before. Purely by the numbers, nearly 235,000 self-published printed volumes came into the market in 2012, compared to just under 302,000 traditionally published books. If you add in e-books, the self-published total jumps to over 390,000 titles.
The leading genres? Romance and literary fiction. 71% of all self-published books are bought by women. The reason for the self-publishing boom? According to authors polled, traditional publishers are a big obstacle to getting published, especially for first-timers and newbies. Also, writers have significantly increased their knowledge of the publishing process itself and are more savvy about formatting, cover design and other elements usually handled by a publishing house.
Here is the original release from Bowker: http://www.bowker.com/en-US/aboutus/press_room/2013/pr_10092013.shtml