ENGLEWOOD, Colo. --It's no secret that football fever sweeps across the nation every autumn, but the NFL's  popularity on television has surged even higher in 2013.

The Broncos' showdown with the Colts on Sunday night marked the 10th time that an NFL game has cracked the 25-million viewer mark this season – up 400 percent from 2012, when only two games had surpassed 25 million viewers at this point in the season, and when only eight games broke the 25 million mark the entire season.

Since Labor Day, NFL games constitute the 16 most-watched TV programs – also up from 11 at this point last year – and no team in the league has captivated attention around the country quite like the Broncos so far this season.

Five of the Broncos' seven games this season have been viewed by 25 million or more people, with Denver's thrilling 51-48 win over the Cowboys on Oct. 6 marking the second-largest viewing audience of the NFL season at 28.3 million. Only the Sept. 8 matchup between the 49ers and Packers was viewed by more people, garnering an audience of 28.5 million.

The Broncos vs. Colts matchup on NBC's *Sunday Night Football *drew the largest audience -- 26.9 million -- for an October NFL primetime telecast since 1992, when the Cowboys and Eagles were viewed by 33 million people. It also ranked as the most-watched October primetime telecast of any kind since 2005.

Denver's victories over the Eagles (26.7 million), Giants (26.4 million) and Ravens (25.1 million) rank fourth, fifth and 10th respectively in the largest viewing audiences for NFL games this season.

Sunday night's game also ignited local television markets – the 49.6 and 49.1 household ratings the game generated in Denver and Indianapolis ranked Nos. 1 and 2 for the week of Oct. 14-20, and NFL games topped ratings in 27 of 30 local markets last week.