The most popular sport in the United States got a little more popular, at least in terms of TV viewership, in 2018.

The NFL stopped a two-year ratings slide and increased its audience across all of its broadcast windows during the regular season, which ended Sunday. Games on CBS, Fox, NBC, ESPN and NFL Network averaged about 15.8 million viewers — slightly below that figure including two games played in London, slightly above without them — an improvement of 800,000 viewers, or 5 percent, on the 2017 season.

The gains in 2018 aren't a complete recovery of the audience the league lost the previous year, but it clawed back about half of 2017's declines. In 2016, NFL regular-season games averaged 16.5 million viewers before falling almost 10 percent to 14.96 million in 2017.

The 2015 season, with a regular-season average of 18.7 million viewers per game, remains the recent high mark for the NFL.

ESPN's Monday Night Football enjoyed the biggest bump among the league's primary broadcast windows. Its average of 11.6 million viewers is an 8 percent improvement over 2017. NBC's Sunday Night Football (19.3 million) and CBS' Sunday-afternoon games (16.5 million) each grew by 6 percent; Fox's Thursday Night Football (14.9 million, including digital) improved by 4 percent on the CBS/NBC broadcasts in 2017; and Fox's Sunday games (18 million) were up 2 percent.

The late-afternoon half of a Sunday doubleheader continues to be the most valuable piece of NFL real estate: Fox averaged 22.05 million viewers for games in that spot, and CBS drew 21.09 million people per week for games with a 4:25 p.m. ET start.

The two most-watched games of the regular season aired on Thanksgiving. Fox's broadcast of Washington at Dallas drew 30.48 million viewers; earlier in the day, CBS averaged 26.5 million with Chicago at Detroit.

Sunday Night Football is on pace to be the No. 1 network show in primetime for the eighth year in a row. Since the start of the Nielsen-designated TV season on Sept. 24, SNF is averaging a 6.1 rating among adults 18-49 the night it airs, way ahead of Thursday Night Football's 4.4.

Even with a week of delayed viewing factored in, SNF tops the closest scripted series by two full points in the demo (4.1 for This Is Us) and more than 1.6 million viewers (17.41 million for The Big Bang Theory).