eReaders and online stores have led to a huge increase in the amount of books being self-published by authors unable or unwilling to follow the traditional route. Last years figures of 391,000 books indicate a 59% increase in self-published releases over 2011, and a 422% increase from 2007.

Self-published books generally refers to independently released titles without the involvement of a commercial publisher. However, the figures also reveal a mere 8 companies offering self-publishing services such as printing, formatting and copyrighting were accountable for 80% of all independent releases.

The latest figures were released by Bowker, who analysed the serial numbers of all self-published book releases in the US. Although these figures might include some duplicate releases - such as hardcover & softcover editions - it’s a general indicator of the vast amount of authors opting to avoid traditional release models. The latest figures also reveal that eBooks account for 40% of serial numbers in the US.

Bowker’s Beat Barblan observes “the most successful self-publishers don’t view themselves as writers only, but as business owners. They invest in their businesses, hiring experts to fill skill gaps and that’s building a thriving new service infrastructure in publishing”. However, in an author survey accompanying the figures, a majority of respondents acknowledged marketing was a major challenge as more and more releases flood the market. For readers, this can also prove a major obstacle given the huge quality discrepancies that are still associated with independent releases.

Predictably, romance novels remain the most popular self-published works, with spiritual and inspirational books the most common non-fiction releases. Bowker has previously revealed women readers accounted for 71% of all sales of self-published books.

While independently released books account for a majority of all releases, this has not yet equated to sales: research estimates only 12% of digital book sales are from authors who have self-published.