The second presidential debate attracted an average audience of 66.5 million viewers Sunday against formidable competition from NFL football.
Nielsen data showed the audience for the face-off at Washington University in St. Louis between Democratic Hillary Clinton and Republican Donald Trump was down 21% from the record-setting 84 million viewers who watched their Sept. 26 debate.
The audience for Sunday's event ranks ninth among presidential debates since 1976, settling in just above the second showdown between President Obama and his Republican opponent, Mitt Romney, on Oct. 16, 2012.
The debate competed with a "Sunday Night Football" contest between the Green Bay Packers and the New York Giants on NBC, which averaged 16.6 million viewers.
News coverage of the leaked audio of Trump's lewd 2005 conversation with Billy Bush on "Access Hollywood" probably drove the debate numbers higher than they would have been otherwise.
CBS had the largest debate audience with 16.4 million viewers. ABC, which had its correspondent Martha Raddatz moderating the debate alongside CNN's Anderson Cooper, had 11.5 million viewers.
CNN was the third-most-watched network carrying the event with 11.3 million viewers, its largest audience for a presidential debate since at least 1996.
Fox News Channel averaged 9.9 million viewers, followed by the Fox broadcast network (5.6 million), MSNBC (5.5 million), PBS (2.9 million), Univision (2.4 million), Fox Business Network (565,000), CNBC (395,000) and Azteca (43,000).
The third and final presidential debate will be held Oct. 19 at the University of Nevada at Las Vegas with "Fox News Sunday" anchor Chris Wallace as moderator.