The losses at CNN continued a pattern in place for much of the last year, as the network trailed its competitors in every prime-time hour. (CNN still easily beats MSNBC in the daytime hours, but those are less lucrative in advertising money, and both networks are far behind Fox News at all hours.)

Image Fox’s Glenn Beck and CNN’s Larry King. Credit... Left, Jose Luis Magana/Associated Press; Fred Prouser/Reuters

About the only break from the bad news for CNN was that March was not as bad as February, when the network had its worst single month in its recent history, finishing behind not only Fox News and MSNBC, but also its sister network HLN — and even CNBC, which had Olympics programming that month.

CNN executives have steadfastly said that they will not change their approach to prime-time programs, which are led by hosts not aligned with any partisan point of view.

But the numbers are stark: For the network’s longest-running host, Larry King, who has always been regarded at CNN as the centerpiece of prime time because he drew the biggest audiences at 9 p.m., the quarter was his worst ever.

Mr. King’s audience dropped 43 percent for the quarter and 52 percent in March. He dropped to 771,000 viewers for the quarter from 1.34 million in 2009. More alarming perhaps, Mr. King, whose show has been regularly eclipsed by Rachel Maddow’s on MSNBC (and is almost quadrupled by Sean Hannity’s show on Fox), is now threatened by a new host, Joy Behar on HLN (formerly Headline News.)