That's the one stamped on the book. And finally authors do not receive a percentage for every book printed, just for every book sold . Below is a chart that gives several possible royalty earnings of a romance author for a single book. The blue cells represent typical royalty earnings and sales for lower midlist single title authors at different royalty rates. The green cells represent typical royalty earnings and sales for higher midlist single title authors at different royalty rates.
Most books have some of both.
This covers the majority of romance authors being published. There are some authors who make more, but it's still a small minority. The book prices are currently typical for this level, and the royalty rates represent the range still existing in the romance publishing world. This chart is meant to explain how people can make vastly different amounts of money for books of the same genre or sales. It should give you an impression of possible royalty earnings, not demonstrate exactly what an author can make for her books.