Note that's a household, not an adults 18-49 rating. For comparison the NFC championship game averaged a 30.6 household rating
via press release:
"THE NFL ON CBS" SCORES WITH HIGHEST RATING FOR AFC CHAMPIONSHIP GAME IN 16 YEARS
CBS Sports' coverage of the 2010 AFC Championship Game featuring the Indianapolis Colts defeating the New York Jets on Sunday, Jan. 24 (3:00-6:15 PM, ET), earned an average overnight household rating/share of 28.4/50. This was the highest rating for the AFC Championship in 16 years (1994, 29.5/57 on NBC). The Jets-Colts rating was up 4% from a 27.4/48 in the comparable early-game window in 2008 with New England defeating San Diego and coverage was up 19% compared to its late-game broadcast of last year's AFC Championship Game which saw Pittsburgh beat Baltimore (23.8/37).
The AFC Championship Game rating peaked at a 32.0/53 from 5:30-6:00 PM, ET.