WASHINGTON — (CNN) Monday night was the most-watched debate in American history.

More than 80 million people tuned in to see Hillary Clinton and Donald Trump face off, setting a new record in the sixty year history of televised presidential debates.

The final numbers are still being tallied by Nielsen. But the debate averaged a total of 80.9 million viewers across 12 of the channels that carried it live.

Nielsen traditionally measures viewers who watch via traditional TV at home. That means people who watched the debate at parties, bars, restaurants, and offices were not counted.

Nor does the 80.9 million viewer total include PBS and C-SPAN.

Ratings for PBS will be available later Tuesday.

Many millions also watched the debate via the Internet.

Various live streams on YouTube together registered more than 2.5 million simultaneous viewers.

Live streams on other sites also reached millions of people.

This means the actual total audience is significantly higher than 80 million.

On the TV side, CNN and other cable news channels saw big increases over past election years.

So did the broadcast networks.

NBC had the biggest audience overall, partly because “NBC Nightly News” anchor Lester Holt was the moderator of the debate.

Upwards of 18 million people watched the debate on NBC.

Nielsen data confirms that viewership stayed high the entire time.

Contrary to some speculation, there was not a big drop-off after the first hour of the 98-minute debate.

The first Obama-Romney debate in 2012 averaged 67 million viewers.

The debate viewership number to beat was 81 million, set back in 1980, when Jimmy Carter and Ronald Reagan debated just once before the election.

Anticipation for the Clinton-Trump meeting had been mounting for months. On Monday night Twitter said it was the “most tweeted debate ever.”

On both Twitter and Facebook, Trump was a livelier subject than Clinton.

Twitter said the “final share of conversation around the candidates on stage” was 62% for Trump and 38% for Clinton.

On Facebook, the results were even more lopsided, with Trump earning 79% share of conversation and Clinton having the remaining 21%.

Being talked about isn’t necessarily a good thing for a candidate.

Most commentators gave Clinton the edge over Trump after the debate.

Still, the post-debate coverage on TV focused on Trump, partly because of surprising and confounding comments he made on stage.

CNN’s reality check team investigated 26 claims made by Clinton and Trump and found that Trump made a greater number of misleading statements.