NielsenThe largest publisher of independent e-books may not surprise you.

Bowker named Smashwords the largest publisher for indie e-books in its latest report “Self-Publishing in the United States, 2007-2012,” after publishing about 90,000 e-books in 2012.

When it comes to e-books and printed books, Amazon’s CreateSpace comes in at number one with 131,000 published ISBN registrations, more than double than what it did in 2011 (59,000).

Bowker based the data on ISBN registrations, which is handled by Bowker. More than 50 publishers were mentioned in the report.

Author Solutions was another name that popped up often with divisions or imprints of the company often making the top 10. Author Solutions printed about 48,000 e-books and print books in 2012, which was down from 52,000 the year before.

Not all books carry an ISBN, but Smashwords says that 92 percent of its books have the unique identifier.

“Although I’m pleased to see Smashwords come in at number one, I’m even more excited about what Bowker’s overall data says about the rise of self-publishing,” Smashwords founder Mark Coker wrote in a recent blog post. “Indie authors are taking publishing matters into their own hands.

“The three most essential requirements of professional publishing – the printing press, the access to retail distribution, and how-to knowledge of professional publishing best practices – are now freely available to all indie authors. Smashwords is committed to providing writers these tools.”

One of Smashwords newest tools is Dropbox integration. Readers will see a new feature on the site “Send to Dropbox” that will transfer purchases to the Dropbox cloud. Dropbox works on many tablets, smartphones and reading devices, giving the option of reading stories on the go.