Tuesday’s debate among the Democratic presidential candidates was the sixth-highest-rated non-sports cable telecast on record, CNN announced today.

Citing Nielsen Fast National ratings data, CNN said the debate, moderated by Anderson Cooper, averaged 15.3 million total viewers. In the key news demo of viewers 25-54, the program averaged 4.8 million — the highest ever for a Democratic debate.

“Prior to last night’s debate, the highest-rated Democratic presidential primary debate on cable news was CNN’s 2008 Los Angeles Debate (1/31/08), which averaged 8.3 million viewers,” CNN reported. “On broadcast, the highest-rated was ABC’s 2008 Philadelphia Democratic debate (4/16/08), averaging 10.7 million viewers.”

The announcement adds: “CNN live streamed the debate to CNN.com, its mobile apps and Apple TV, setting an all-time record for peak concurrent streams of a live news event. At 10:20 p.m., usage peaked at 980,000 concurrent streams, topping the 921,000 peak concurrent streams CNN saw of its GOP debate at Reagan Library. For comparison, it’s estimated that NBC pulled in 1.3 million peak concurrent streams of the Super Bowl earlier this year. ”