The latest cable ratings have a channel at No. 1 that will probably surprise you. EW.com’s Inside TV reports that FXX’s 12-day, 552-episode “Simpsons” marathon lifted the fledgling channel to the top of the cable ratings for adults 18-49 in prime time from Aug. 1 to Sept. 1.

The FX spinoff’s rise pushed cable heavyweight ESPN to No. 2 in the key demo, the report notes.

“Among total viewers, FXX managed to rank a very impressive ninth. Episodes averaged 1.3 million viewers and 841,000 adults 18-49 in prime time, with an estimated 25 million people sampling the marathon at some point,” the report adds.

Before airing the marathon, FXX ranked 49th among all cable networks in the 18-49 segment, the piece notes.