The NFL entered the halfway point of its season with a nominal increase over last year, capped by a blockbuster number for Chiefs-Bills.

NFL regular season games averaged 17.8 million viewers through the halfway point of the season, per a combination of Nielsen and Adobe Analytics — up 7% from last year and the highest nine-week average since 2015. The 7% increase is within the range that can potentially be accounted for by Nielsen’s methodological changes this year, specifically its February expansion of out-of-home viewing and September shift to “Big Data + Panel” methodology.

The two most-watched windows so far this season both involved the Chiefs in standalone 4:25 PM windows, the first being their Week 2 Super Bowl rematch with the Eagles — which averaged nearly 34 million viewers on FOX.

The second came this past week as the latest chapter of the Chiefs-Bills rivalry averaged a 14.3 rating and 30.84 million on CBS last Sunday — up 21% in ratings and 27% in viewership from last year’s Week 9 national window on FOX (11.8, 24.21M).

The Bills’ win, which peaked with 35.2 million, helped CBS to its fifth-largest Sunday audience during the regular season since it resumed airing NFL games in 1998. The Chiefs-Bills rivalry accounts for two of the network’s top five, with the teams’ Week 11 meeting last season placing second (31.1M).

In a rarity, CBS delivered the top two NFL audiences of the week, with the network’s early window (mostly Colts-Steelers) averaging an 8.8 and 18.46 million — the largest audience for that window in Week 9 of the season since the network reacquired rights.

Placing third, the latest edition of ESPN’s “Monday Night Football” (Cardinals-Cowboys) averaged a combined 16.2 million across ABC, ESPN, ESPN2 and ESPN Deportes — actually down 22% from Buccaneers-Chiefs in Week 9 last year (20.7M) and the least-watched “MNF” game to air on both ESPN and ABC this season.

Viewership was conspicuously soft given the ongoing blackout of Disney networks on YouTube TV. Despite featuring the Cowboys, “MNF” drew fewer viewers in Week 9 than the prior week, when Commanders-Chiefs aired opposite Game 3 of the World Series and still drew 17.6 million. It also drew fewer viewers than Buccaneers-Lions in Week 8, which aired in a special early window as part of an “MNF” doubleheader and still drew 18.8 million.

But despite the lower numbers, “MNF” was the most-watched primetime window of Week 9 — finishing ahead of NBC’s “Sunday Night Football” for just the second time this season. “SNF” averaged a season-low 8.1 and 15.61 million for its pairing of the Seahawks and Commanders, down from an 8.3 and 16.18 million for Colts-Vikings last year. (Figures including Adobe Analytics were not immediately available.)

In a real rarity, “SNF” ranked second-to-last among NFL windows in Week 9, trailing even the FOX singleheader at a 7.5 and 16.04 million.

“Thursday Night Football” rounded out the Week 9 slate with a 5.7 and 12.36 million for Ravens-Dolphins last week. Officially, that marks a 7% increase in viewership over Texans-Jets last year (11.56M), but keep in mind that it is official Nielsen policy to compare “Big Data + Panel” figures to last year’s panel-only numbers.

While “Big Data + Panel” only became official Nielsen currency in September, it had been tracked the prior two years. As Amazon regularly publicized those viewership figures, it is possible to make an apples-to-apples viewership comparison. Compared to last year’s “Big Data” figure for Texans-Jets, this year’s game actually declined 4% from 12.82 million.

Prime Video is averaging 14.95 million viewers for “TNF” through the halfway point, officially up 15% from the same point last year (13.0M). But compared to the “Big Data” average Amazon publicized last year, the nine-week average is up 6% from 14.07 million.