Fast National ratings for Thursday, February 18, 2010.
 
If you continue to be unsure why NBC's rivals scheduled mostly repeats against the Winter Olympics, have you not paid attention this week?
 
Although Wednesday's Olympics decimation of "American Idol" ought to have been evidence enough, look no further than "Grey's Anatomy," which aired one of its more innovative episodes on Thursday and yet drew season lows opposite the snowboarding and figure skating. CBS' "Survivor: Heroes vs. Villains" was also down, while FOX's "Past Life" and ABC's "Deep End" practically dropped off the schedule entirely.
 
Among adults 18-49, NBC averaged a 7.1 rating, topping ABC and CBS' 2.5 ratings in the key demographic. FOX's 1.3 rating and the 0.7 rating for The CW trailed.
 
Overall, NBC averaged an estimated 25.3 million viewers to go with a 14.7 rating/23 share. CBS was a distant second with a 5.9/9, followed by the 4.9/8 for ABC. FOX's 2.9/5 was fourth, beating the 1.1/2 for The CW.
 
NBC swept the primetime hours starting at 8 p.m. with the 14.1/22 for the start of the Olympics coverage, which also had a 6.2 demo rating. CBS' "Survivor: Heroes: vs. Villains" was second with a 6.9/11 and did a 3.9 demo rating. FOX's "Bones" repeat was third, beating the 3.0/5 for a new "Deep End" on ABC, doing only a 1.1 demo rating. The CW's repeat of "Vampire Diaries" had a 1.1/2 for fifth. 
 
The Olympics improved to a 16.2/25 for NBC in the 9 p.m. hour. "Grey's Anatomy" could muster only a 6.6/10 and a 3.7 demo for second. CBS' "The Mentalist" repeat was third with a 5.7/9. FOX's new "Past Life" had a 2.2/3 and drew under 3.5 million viewers. That left The CW in last with a "Supernatural" repeat.
 
In the 10 p.m. house, the Olympics slipped to a 13.9/23, a big odd given that that was when NBC finally got around to the heavily promoted figure skating long program. CBS' repeat of "CSI: Crime Scene Investigation" was second overall. ABC's new "Private Practice" had a 5.1/8 for third overall, but finished second in the demo with a 2.8 rating.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.