NFL television ratings fell 9.7 percent during the 2017 regular season, according to numbers registered by Nielsen.

A typical game was watched by 1.6 million fewer people this season as compared to last season (14.9 million versus 16.5 million).

The drop comes after the NFL had hoped to stem an 8 percent ratings slide from last season by experimenting with the format for television commercials and trying to speed up the game.

Last year's slide was partly attributed to a lost audience due to the presidential election. This year, the NFL was challenged with fans upset at players protesting during the national anthem, an action that led to a league faceoff with President Donald Trump.

Other factors cited include the dilution of the product through Thursday Night Football, which was broadcast on the NFL Network, CBS, NBC and Amazon Prime in 2017. This season, both Fox CEO James Murdoch and CBS Sports Chairman Sean McManus blamed the ratings slide on the proliferation of games.

The NFL RedZone also might be a factor in taking fans away from watching the daytime games on CBS and FOX. The NFL Network and DirecTV, which air separate versions of the show that broadcast live look-ins, have never shared viewership numbers.

The NFL isn't in a vacuum, as the viewership drop is indicative of the general environment as less television is being watched and cable subscriptions have declined. The NBA, however, has seen a 20 percent increase in viewership this season as compared to 2016-17.

Despite the drop in NFL ratings, Nielsen data shows that the 20 of the 30 highest-rated shows on television in 2017 were football games. Both NBC and ESPN had the most-watched shows every single week, in terms of audience and in all key male demographics, for Sunday Night Football and Monday Night Football games this season.

NBC's Sunday Night Football finished first in prime time this fall for the seventh consecutive year, besting "American Idol" (2005-06 through 2010-11) for the longest hold on the top prime-time spot since 1950. Its 18.2 million viewers beat the second-best prime-time show, Thursday Night Football on CBS, by 29 percent -- its largest margin ever.

ESPN officials reported earlier in the week that the network grew its total day viewership in 2017 by 1 percent, while prime time was up 7 percent.