Bowker is the leading provider of bibliographic information and management solutions for the publishing industry in the USA. Earlier this month Bowker released a detailed six-page report on self-publishing. The data presented in the report is based on counts of ISBNs registered in Bowker's Books in Print database and published or distributed in the United States. The report, titled Self-Publishing in the United States 2008-2013, features analysis of self-publishing service providers, micro-publishers and direct output from authors publishing with their own block of registered ISBNs. Bowker has been correlating the data in yearly reports since 2006, though the first annual report was only released to the media in 2011. The full report can be downloaded in PDF here.