A new report says that there are thousands of small publishers in America “earning between $1 million and $50 million on their own, but adding up to an estimated $11 billion market. Traditional studies released by the study group, the Association of American Publishers and others assume that the solid majority of book sales comes from the larger organizations, with the top 50 making at least $20 billion out of a $28 billion market. Wednesday’s report, titled “Under the Radar,” asserts that the industry is both larger and less concentrated than previously believed.”