Fast National ratings for Thursday, April 22, 2010.
 
CBS' "Survivor: Heroes vs. Villains" spent another week as Thursday's top show in the demo, while "The Mentalist" drew the night's biggest audience. And, as usual, CBS ended Thursday in first in the key measures.
 
Meanwhile, FOX's "Bones" and "Fringe" were both down for the week, as were the returns of NBC's comedies, while ABC's "FlashForward" was inexplicably up. Also, ABC's experiment with a 9 p.m. "Private Practice" wasn't a disaster, nor was it hugely encouraging.
 
Among adults 18-49, CBS averaged a 3.1 rating, better than the 2.3 rating for FOX, or NBC's 2.2 rating. ABC was fourth in the key demo with a 1.7 rating, with The CW's 1.4 rating close behind.
 
Overall, CBS averaged an estimated 13.3 million viewers in primetime to go with an 8.1 rating/14 share. FOX was a distant second with a 4.6/8, with ABC's 4.0/7 taking third. NBC was fourth with a 3.1/5, with The CW's 1.8/3 trailing.
 
CBS swept the primetime hours, starting at 8 p.m. with the 7.0/12 and 3.6 demo rating for "Survivor: Heroes vs. Villains." FOX's "Bones" was second with a 5.6/9 and in the demo with a 2.5 rating. ABC's "FlashForward" did a 3.7/6 and 5.56 million viewers, a noticeable bump from last week. NBC's "Community" and "30 Rock" finished fourth overall and third in the demo. The CW's "The Vampire Diaries" was fifth with a 2.0/3 and 3.27 million viewers, though the vampire soap fell back behind "FlashForward" in the key demo this week after topping ABC last week.
 
In the 9 p.m. hour, CBS' "CSI: Crime Scene Investigation" did an 8.2/13 to win the hour. ABC's "Private Practice," airing without its normal "Grey's Anatomy" lead-in finished second overall with a 5.1/8 and third in the demo. NBC's "The Office" and "30 Rock" tied with FOX's "Fringe" with a 3.6/6 overall. While "Fringe" topped the NBC comedies in total viewers, the NBC comedies actually won the hour in the 18-49 demo with a 2.9 rating, while FOX was fourth with a 2.1 rating. The CW's "Supernatural" was fifth, in line with its season averages.
 
"The Mentalist" won the 10 p.m. hour for CBS with a 9.3/16 and a 3.0 demo rating. ABC's repeat of "Grey's Anatomy" was second overall, beating the 2.9/5 for NBC's "Marriage Ref," though "Marriage Ref" was second in the demo.
 
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.