Turns out, sex doesn't always sell, especially if there's a good football game on NBC.

Despite the headline-grabbing news of Donald Trump speaking in lewd and tawdry terms about women in a 2005 audio recording, the Republican presidential nominee's second debate with Democrat Hillary Clinton attracted a smaller audience than their first head-to-head matchup on Sept. 26.

According to Nielsen, an estimated 66.5 million people watched the debate held at Washington University in St. Louis, compared with a record-setting 84 million two weeks ago. Roughly 4 million people streamed the debate over a variety of websites.

The first debate broke a record set in 1980 between Ronald Reagan and Jimmy Carter, hearkening back to a time when there were only a handful of television channels from which to choose.

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Speculation ran high heading into Sunday's debate that the publication of the video recording, in which Trump boasts about groping and kissing women, would spark a surge of viewers. As expected, discussion of the recording, made public on Friday by The Washington Post, set the tone for a debate filled with invective, personal attacks and name-calling.

Yet the total audience ended up being lower either because of debate fatigue or because NBC, a unit of Comcast (CMCSA) - Get Comcast Corporation Class A Report , televised an NFL game between the New York Giants and Green Bay Packers. NBC viewers were encouraged by the company to watch the football game on TV and stream the debate over an NBC station. 

CBS (CBS) - Get CBS Corporation Class B Report led all networks with 16.5 million viewers, topping all rivals among the advertiser-coveted demographic of 25- to- 54-year-olds with an audience of 6.4 million. Disney's (DIS) - Get Walt Disney Company Report ABC was second with 11.5 million total viewers, though Time Warner's (TWX) CNN attracted a larger audience in the key demographic with an audience of 4.8 million, compared with 4.6 million for ABC.

CNN's total audience was 11.3 million, placing it third. CNN likely benefited from having the debate co-moderated by Anderson Cooper, its best-known anchor. Martha Raddatz of ABC was the other moderator.

21st Century Fox's (FOXA) - Get Fox Corporation Class A Report Fox News Channel attracted 9.9 million viewers, while its flagship network generated an audience of 5.6 million. Comcast's MSNBC drew a total of 5.5 million viewers. 

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