The Trump bump shows up in presidential debate ratings, but how do these clashes compare?

One of television's most-watched events is coming up on Thursday: the first debate of the 2024 presidential election.

President Joe Biden and former president Donald Trump will engage in a rematch after a dramatic series of debates (and cancellations) ahead of the 2020 election. This debate is happening earlier than usual and without the Commission on Presidential Debates as the host. The two candidates are expected to talk age, immigration, abortion and Trump's criminal record.

Trump's first appearance on the presidential debate stage in 2016 as he faced Democratic nominee Hillary Clinton was the most watched presidential debate in history, according to Nielsen total viewership data. But other metrics show 1960 was the year the greatest proportion of households tracked by Nielsen tuned in.

Here is a look back at the presidential debates and the viewers they brought in:

Presidential debate ratings: How many people watched the presidential debate? Check the ratings for Trump-Biden debate

What are Nielsen ratings and what do they mean?

Nielsen is a media research company that tracks audience data.

For election coverage audience, Nielsen measured the total number of viewers older than 2, the number of households that tuned in, and a rating as a percentage showing the proportion of television-owning households that tuned in, according to Pew Research.

LIVE UPDATES: Presidential debate: How to watch Donald Trump, Joe Biden battle in Atlanta

The data does not encompass everyone who streamed the event, watched it online, who watched on laptops or cell phones, but no company reliably captures the entire audience, according to the New York Times.

First debate of the season usually draws the biggest viewership

Historically, the first debate in the presidential election cycle draws the biggest crowd, however the first debate usually happens in September, after the candidates have been formally nominated.

In 2020, the first debate between Biden and Trump drew 73.1 million viewers while the last debate saw 62.9 viewers, according to Nielsen. The second debate was canceled when Trump refused to participate remotely during a White House COVID-19 outbreak.

In 2016, the first debate between Trump and Clinton drew 84 million views, the second debate drew 66.5 million views and and the final debate drew 71.6 million views.

Presidential debate ratings, ranked

According to Pew, debate viewership as a share of total TV audience has fallen over the last 70 years. Plus, Nielsen's ratings, based on the percent of TV-owning households tuned in, may not capture the full picture today compared to the first debate in 1960, as more people move to streaming.

But here is how the Nielsen ratings compare between each debate:

2020: Biden and Trump

• Debate 1: 40.2%

• Debate 2: Canceled

• Debate 3: 35.3%

Note: Nielsen also included out-of-home viewing and connected TV in the totals in 2020.

2016: Trump and Clinton

• Debate 1: 47.6%

• Debate 2: 37.1%

• Debate 3: 41.7%

2012: Barack Obama and Mitt Romney

• Debate 1: 40.4%

• Debate 2: 40%

• Debate 3: 35.9%

2008: Obama and John McCain

• Debate 1: 31.6%

• Debate 2: 38.8%

• Debate 3: 35%

2004: George W. Bush and John Kerry

• Debate 1: 39.4%

• Debate 2: 29.6%

• Debate 3: 32.6%

2000: Bush and Al Gore

• Debate 1: 31.7%

• Debate 2: 26.8%

• Debate 3: 25.9%

1996: Bill Clinton and Bob Dole

• Debate 1: 31.6%

• Debate 2: 26.1%

1992: Bill Clinton, George Bush and Ross Perot

• Debate 1: 38.3%

• Debate 2: 46.3%

• Debate 3: 45.2%

1988: Bush and Michael Dukakis

• Debate 1: 36.8%

• Debate 2: 35.9%

1984: Ronald Reagan and Walter Mondale

• Debate 1: 45.3%

• Debate 2: 46%

1980: Reagan and Jimmy Carter

• Debate 2: 58.9%

1976: Carter and Gerald Ford 

• Debate 1: 53.5%

• Debate 2: 52.4%

• Debate 3: 47.8%

1960: John F. Kennedy and Richard M. Nixon

• Debate 1: 59.5%

• Debate 2: 59.1%

• Debate 3: 61%

• Debate 4: 57.8%

There were no televised presidential debates in 1964, 1968 or 1972, according to Nielsen.

What time is the CNN Presidential Debate?

The CNN Presidential Debate is scheduled for 9 p.m. ET on Thursday, June 27.

This article originally appeared on USA TODAY: Biden vs. Trump is Thursday. Past presidential debate ratings compared