Cable television benefited from huge ratings Monday for broadcasting the opening night of the Democratic National Convention.

Twenty-two million viewers, which is a 20 percent larger audience than in 2004, tuned in to watch Michelle Obama’s speech, according to Nielsen Media Research.

According to the Boston Herald, Tobe Berkovitz, associate dean at Boston University’s College of Communication, said that the big numbers prove that people are still very much interested in the presidential campaign.

“You get 22 million people to watch a political convention - that’s not chopped liver,” Berkovitz said. “Those are spectacular numbers considering it’s not a Clinton or the nominee who’s speaking.”

According to Nielsen estimates, NBC averaged 4.71 million viewers from 10 p.m. to 11 p.m., the hour that included Michelle Obama’s speech. The second is CNN, with 4.27 million people watching. CNN is followed closely by ABC (4.17 million). Then came CBS (3.46 million), Fox News (2.92 million) and MSNBC (2.10 million). This was a success for CNN, which had not beaten any broadcast networks in such competitions.

All the six TV networks recorded 18.4 million viewers for the first night in 2004, Nielsen reported.

About 27.7 million people tuned into the Beijing Olympics each night on NBC, while Sunday night’s closing ceremony drew about 27.8 million viewers.

The three major networks, ABC, CBS, and NBC, plan to air an hour of live Democratic National Convention coverage each night at 10 p.m.