CBS found the ratings end zone in a big way Sunday, with the AFC championship game putting a cap on the first half of a season that has the Eye leading its rivals across the board.

The last time CBS was the January leader in adults 18-49 was 17 years ago; nevertheless, the net holds a 5% lead on ABC and a 10% advantage over NBC through 18 weeks of the season, according to Nielsen. Fourth-place Fox, meanwhile, is lurking in the wings after a boffo start for the fourth edition of “American Idol” last week, and it will get a nice boost from the upcoming Super Bowl.

Even looking only at regularly scheduled programs — a more accurate barometer of a net’s series performance — CBS holds a 4% advantage over ABC in adults 18-49, a 7% lead over NBC and a big 37% cushion on Fox.

CBS also enjoys a sizable edge on its rivals in both adults 25-54 (5.0/12) and total viewers (13.1 million), two categories it won last season as well.

Among new series, dramas continue to be where the Nielsens are — even though a record 14 unscripted series have debuted on the six nets since September.

Dramas top newcomers

Season’s top five new programs in adults 18-49 are all dramas: ABC’s “Desperate Housewives” (10.3 rating/22 share) and “Lost” (6.2/17), NBC’s “Medium” (6.1/15 for its four episodes), CBS’ “CSI: NY” (5.3/14) and ABC’s “Boston Legal” (5.0/12).

Also keep an eye on CBS crime hour “Numbers,” which received significant sampling in a post-football preview episode Sunday and bows this week in its regular Friday-at-10 slot, where no program dominates.

Season’s No. 1 new comedy is NBC’s “Joey” (sixth overall in 18-49 with a 4.8/14); the same net’s “The Biggest Loser” is tied with ABC’s “Wife Swap” as the top-rated new unscripted program (seventh, 4.3/11).

The Jan. 17-23 frame, meanwhile, was dominated by Fox’s opening three hours of the fourth edition of “American Idol” and Sunday’s American Football Conference title game on CBS, which aired mostly in primetime — both of which likely drew additional viewers as the result of heavy snowstorms in the Northeast.

“Idol” opened bigger than ever on Tuesday (14.0/33 in adults 18-49, 33.57 million viewers overall) and then had another huge showing Wednesday (11.2/27 in 18-49, 26.71m).

Kicking off

The Tuesday “Idol” perf had ranked as the season’s No. 1-rated night and telecast but then was surpassed Sunday by football on CBS (17.6/39 in 18-49, 44.33m for Patriots-Steelers) — the most-watched AFC championship game in seven years. That led into a special preview of the net’s latest crime drama, “Numbers” (9.2/21 in 18-49, 24.92m), which held onto a good chunk of the football aud.

Although not an official premiere, Sunday’s “Numbers” stands as the season’s highest-rated drama opener.

Another new drama, Fox’s “Point Pleasant,” did OK in its Thursday timeslot premiere (2.6/6 in 18-49, 5.55m), although that was half of what it did in a special post-“Idol” Wednesday preview. Same net’s “Jonny Zero” isn’t doing much on Friday (2.0/6 in 18-49, 4.29m).

For CBS, new unscripted skein “Wickedly Perfect” (2.6/7 in 18-49, 7.76m) dropped further in its Thursday slot and will move to Saturday beginning this week. And first-year comedy “Center of the Universe” (3.5/8 in 18-49, 9.32m) lost more than 20% of its “King of Queens” lead-in on Wednesday and is being benched.

ABC and NBC actually saw some positive developments during the week, despite getting knocked out by the big events on CBS and Fox.

The Peacock was paced by a strong Thursday (opposite soft CBS competish), as “Joey” racked up its best numbers since November (5.3/15 in 18-49, 12.55m); “Apprentice 3” (7.4/18 in 18-49, 15.55m) opened higher than “Apprentice 2”; and “ER” won easily at 10 (8.7/22, 18.82m).

Also, both Tuesday’s “Law & Order: SVU” (5.9/15 in 18-49, 15.34m) and Wednesday’s “Law & Order” (4.7/12, 15.12m) led their timeslots.

ABC was paced by biggies “Desperate Housewives” (11.2/22 in 18-49, 25.95m) and “Lost” (7.4/18 in 18-49, 19.69m), which shined opposite atypically brutal competish.

In the evening news derby, NBC’s “Nightly News with Brian Williams” (3.2/11 in adults 25-54, 11.53m) opened up its biggest advantage to date over ABC’s “World News Tonight with Peter Jennings” (3.0/10, 10.41m) in a frame that included the second inauguration of President Bush. CBS’ “Evening News with Dan Rather,” meanwhile, fell even further behind the pack (2.3/8 in 25-54, 8.00m).

Sci Fi starters

On cable, Friday saw the winter preem of Sci Fi’s entire lineup (“Stargate SG-1,” “Stargate Atlantis” and “Battlestar Galactica”). Latter led the way with a 1.4/4 in 18-49 and 2.86 million viewers overall, helping the net win the night among basic cablers in 18-49, 25-54 and male demos.

Also Friday, USA’s “Monk” opened its winter season with a 1.7/5 in 18-49 and 5.51 million viewers overall.

TBS was the week’s leader in 18-49 (0.91 rating), led by the latest airing of “Miss Congeniality” on Saturday (1.7/5 in 18-49, 4.25m).

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On Monday of the current week, NBC’s “Medium” (6.2/15 in 18-49, 15.78m) again looked good, winning the 10 o’clock hour over a repeat of “CSI: Miami” on CBS (5.3/13, 14.96m) and ABC’s “Supernanny” (3.9/10, 9.25m). Latter was up a bit in demos vs. its week-earlier preem.

Also of note was great numbers for the WB’s unstoppable “7th Heaven” (3.0/7 in 18-49, 7.99m). The birth of Lucy Camden’s baby generated the family drama’s highest scores since 2003 in adults 18-34 (3.4/10), persons 12-34 (3.5/11) and femmes 12-34 (5.6/15) — standing as television’s No. 1 program of the night in the latter.

And Fox’s “24” (5.1/12 in 18-49, 12.20m) continues to outperform its year-ago averages, moving back ahead of NBC’s “Las Vegas” (4.8/11, 12.38m) to win its hour in 18-49.