According to a new report by Bowker, which provides ISBNs for books in the United States, self-publishing has increased by 287 percent in the last five years, accounting for 43 percent of all print books in 2011. Printed versions accounted for almost two-thirds of self-published titles as of last year, but ebooks are on the rise: Bawker notes that self-published ebooks grew by 129 percent from 2006 to 2011, while traditional print books increased by 33 percent in the same period.

Bowker also revealed which producers were most responsible for the blossoming platform, with Amazon's CreateSpace leading the print segment and Smashwords dominating the digital market. As pointed out by paidContent, Bowker does not take Kindle Direct Publishing titles into consideration since they do not have ISBNs, so the actual number of self-published ebooks is likely much higher than the 87,201 titles mentioned in the report.