A study included in Inside Radio provides further insight into the popularity of AM radio formats. Looking at AM stations across the country, the most popular format is talk, which appears on 680 stations. The second most popular format is religious teaching (512) stations, followed by sports (503), news/talk (398), and classic hits (293), all of which round out the top five. Also, according to Inside Radio, two New York stations (WCBS 880 and WABC 770) have the highest cume among AM radio stations in the U.S.
You can see the complete Report in Inside Radio here.