The number of self-published books produced annually in the U.S. has nearly tripled, growing 287% since 2006, with 235,625 print and e titles released in 2011, according to a new analysis of data from Bowker. The research found that while production increases are occurring in both print and e-book formats, the latter is driving the greatest percentage gains. It also shows that while self-publishing may seem like a cottage industry, it is dominated by large firms that offer publishing services to individual authors.

Bowker’s research into self-publishing was prompted by an earlier study that showed 2011’s 148,424 self-published print books represented about 43% of that year’s total traditional print output. While print accounts for 63% of self-published books, e-books are gaining fast. E-book production in 2011 was 87,201, up 129% over 2006. Print grew 33% in the same period.

While self-publishing is a DIY undertaking, Bowker’s analysis shows its infrastructure is made up of a handful of large firms. In 2011, CreateSpace dominated the print segment, supporting the creation of 58,412 titles (39% of self-published print books). Smashwords topped the e-book producers with 40,608 titles (nearly 47% of total self-published e-books). The combined divisions of Author Solutions (now part of Penguin Group) produced a total of 47,094 titles and Lulu Enterprises checks in with 38,005 titles. The Bowker analysis shows that beyond these four players, no company has more than 10% of market share.

Small presses, a category that is defined as publishers who have produced 10 or fewer books, accounted for 34,107 self-published titles in 2011 divided between 21,256 print books and 12,851 e-books.

Bowker's "Self-Publishing Report" is available at