CBS had a great streak going so far this season.

While other networks had a third or even half their schedule below the 4.0 household rating mark, CBS had never really approached that ground. In fact, it hadn't even come close.

That's one of the key reasons, besides having the most-watched scripted shows, that CBS had won 14 of the past 18 weeks of the 2009-10 campaign. But that streak is now over.

"Gary Unmarried" earned a 3.8 rating/6 share in Fast National ratings from The Nielsen Co. Wednesday, the lowest rating CBS received this season for a new non-news, non-event program. It was a 21 percent drop from its season high 4.8/8 Dec. 16, and likely was just the victim of "American Idol" on Fox.

"American Idol," by the way, posted a 15.8/24 and a 14.0/22 in overnight ratings Wednesday, second this season only to ... you guessed it, "American Idol." The premiere Tuesday earned a 16.8/25 and a 15.0/22.

That, so far, has propelled Fox to the top of the ratings heap for the first time since it launched a light schedule ahead of the other networks the week of Sept. 6. Fox is averaging an 11.3/17 after seven programs through Wednesday while CBS has a 7.9/12 through 13 episodes this week, beginning on Sunday.

Fox, however, doesn't have "American Idol" the rest of the week. Instead, it's new episodes of "Bones" and "Fringe" Thursday and a new episode of "Dollhouse" on Friday. If those shows were to earn the same ratings they did in their last outing, Fox could still be looking at the best weekly ratings of the season with a 9.1/14. The previous high came from ABC the week of Sept. 20 when it earned an 8.8/14 during a week it aired 13 episodes, but didn't have a single show finish below a 5.5 household rating (including "Eastwick.")

Even with a 1.5 household rating from "Dollhouse," Fox should easily secure its second weekly win of the season, and the first since the beginning of September.

Fast Nationals usually provide a snapshot of what Americans are watching by pulling numbers from the top urban markets that includes both live viewing and same-day timeshifted viewing. A rating point generally represents more than 1.1 million households while the share indicates the percentage of televisions turned on that was tuned to the specific program. These numbers typically shift when final ratings are issued.

Data collected from The Nielsen Co., as distributed by Zap2it. BlipNetwork tracks non-news, non-event programming, and figures for this story reflect airing of new episodes only. For more information on the Audience Loyalty Index, click here.