Fox News Channel continued to maintain a formidable lead in the cable news competition during February in spite of showing some erosion among the 25- to 54-year-old viewers considered the key news demographic group.

Second-place CNN posted widespread ratings growth but saw its longtime signature show “Larry King Live” log double-digit year-to-year decreases in total viewers and among 25 to 54.

MSNBC’s 7 p.m. and 8 p.m. programs, “Hardball” and “Countdown With Keith Olbermann,” beat their CNN counterparts, “The Situation Room” and “Paula Zahn Now,” in the 25 to 54 demo.

According to data from Nielsen Media Research, Fox averaged 856,000 total viewers for total day in February, up 5 percent year to year, followed by CNN with 426,000, up 12 percent, and MSNBC with 273,000, up 39 percent (the latter’s schedule included news and Olympics programming).

In prime time, Fox averaged 1.49 million total viewers (down 5 percent year to year), followed by CNN with 657,000 (up 3 percent) and MSNBC with 357,000 (up 24 percent).

In the news demo for total day, Fox averaged 236,000 viewers (down 13 percent year to year), followed by CNN with 131,000 (up 4 percent) and MSNBC with 116,000 for its news and Olympics programming (up 47 percent).

In the news demo in prime time, Fox averaged 344,000 viewers (down 21 percent year to year), followed by CNN with 190,000 (up 3 percent) and MSNBC with 153,000 (up 35 percent).

Mr. King averaged 901,000 total viewers for the month, down 12 percent from February 2005, and 228,000 viewers in the 24 to 54 demo, down 15 percent year to year.

Despite declines, “Larry King Live” once again broke Fox News Channel’s stranglehold on the top 12 cable news programs by finishing 10th for the month.

In ninth place: “Fox and Friends,” the morning show that averaged 859,000 viewers, more than any of CNN’s prime-time shows.

MSNBC’s “Hardball” at 7 p.m. averaged 400,000 total viewers and 176,000 viewers in the demo (up 91 percent year to year). “Countdown” averaged 400,000 total viewers and 164,000 viewers in the demo (up 56 percent).

In other highlights, Headline News saw marked year-to-year improvements in its year-old prime-time lineup but more modest improvements for total day.

For total day Headline News averaged 224,000 viewers (up 7 percent) and 97,000 viewers in the demo (up 10 percent). The prime-time averages were 347,000 total viewers (up 73 percent) and 122,000 in the demo (up 61 percent). The prime-time sparkplug “Nancy Grace” averaged 583,000 total viewers (up 146 percent) and 168,000 in the demo (up 110 percent).

CNN’s “Anderson Cooper 360” averaged 550,000 viewers (up 32 percent year to year) total viewers from 10 p.m. to midnight and 192,000 viewers in the demo (up 39 percent).