Have you ever asked yourself what are the most profitable book genres? Maybe out of simple curiosity, or because you are looking to write new content, either a book or just a new blog?

According to bookstr.com, here are the five most profitable genres, per US billion/million sales:
Romance and Erotica - $1.44 billion
Crime/Mistery - $728.2 million
Religious/Inspirational - $720 million
Science Fiction/Fantasy - $590.2 million
Horror - $79.6 million