The broadcast of the Democratic presidential primary debate in Las Vegas on Wednesday drew nearly 20 million viewers across NBC and MSNBC, making it the most-watched Democratic debate in television history, the network said.

The debate, which featured former New York City Mayor Michael Bloomberg Michael BloombergTop Democratic super PAC launches Florida ad blitz after Bloomberg donation The Hill's 12:30 Report - Presented by Facebook - Latest with the COVID-19 relief bill negotiations The Memo: 2020 is all about winning Florida MORE alongside the other Democratic candidates for the first time, averaged about 19.7 million viewers, according to Nielsen Fast National Data.

An average of 5.3 million viewers in the 25–54 age demographic watched the debate across the two networks, a new high among that demographic as well. NBC said that an additional 13.5 million people live streamed the event, which took place just days ahead of the Nevada caucuses.

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The previous viewership high came the night of the second Democratic primary debate of the 2020 election cycle. Nearly 18.1 million Americans watched the June 2019 debate across NBC, MSNBC and Telemundo. The most recent numbers do not account for viewership on Telemundo.

The high viewership came as Sen. Bernie Sanders Bernie SandersKenosha will be a good bellwether in 2020 Biden's fiscal program: What is the likely market impact? McConnell accuses Democrats of sowing division by 'downplaying progress' on election security MORE (I-Vt.) has appeared to emerge as the front-runner among the remaining field, and he was targeted by several of his opponents on Wednesday.

In addition, Bloomberg, the billionaire businessman self-funding his campaign, has climbed in national and state-specific polls in recent days. During the debate, he faced an onslaught of attacks over policies such as stop-and-frisk policing and his past comments about women.

The first GOP primary debate of the 2016 election cycle still holds the record for TV viewership of a debate regardless of party. That debate, which featured then-candidate Donald Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE sparring with Republican primary opponents for the first time, earned Fox News an average of 24 million American viewers.