Fast National ratings for Thursday, September 6, 2012.
 
A low-rated installment of "America's Got Talent" and coverage of the Democratic National Convention helped NBC overcome "Big Brother"-driven CBS on Thursday night.
 
Among adults 18-49, NBC averaged a 2.0 rating, topping CBS' 1.6 rating in the key demographic. ABC was third with a 1.1 rating, followed by the 0.7 key demo rating for FOX and The CW's 0.3 key demo rating.
 
Overall, NBC averaged an estimated 7.22 million viewers and a 4.6 rating.7 share for Thursday primetime. CBS was far back in second with a 3.3/5 and 5.3 million viewers, topping the 2.8/4 and 4.33 million viewers for ABC. FOX averaged only a 1.2/2 and 1.82 million viewers for Thursday, with The CW averaging a 0.5/1 and 709,000 viewers.
 
8 p.m. - NBC's "America's Got Talent" averaged 7.595 million viewers and a 1.8 rating among adults 18-49 for the 8 p.m. hour, compared to the 6.78 million viewers and 1.8 key demo rating for CBS' repeats of "The Big Bang Theory" and "Two and a Half Men." ABC's "Wipeout" was far back in third with 4.48 million viewers and a 1.3 key demo rating. On FOX, repeats of "Raising Hope" and "New Girl" averaged 1.86 million viewers and a 0.7 key demo rating, topping the 788,00 viewers and 0.3 key demo rating for The CW's "Vampire Diaries" repeat.
 
9 p.m. - A double-elimination episode of "Big Brother" let CBS claim the 9 p.m. hour, averaging 6.09 million viewers and a 2.2 rating among adults 18-49. NBC was a close second with 6.03 million viewers and a 1.6 key demo rating for Democratic Convention coverage. ABC's "Rookie Blue" averaged 4.83 million viewers and a 1.2 key demo rating in third, far ahead of the 1.78 million viewers and 0.6 key demo rating for FOX's "Glee" repeat. The CW's new episode of "The Next" averaged 629,000 viewers and a 0.3 key demo rating.
 
10 p.m. - NBC's Democratic Convention coverage, highlighted by President Obama's speech, averaged 8.03 million viewers and a 2.5 rating among adults 18-49 for the 10 p.m. hour. ABC's DNC coverage averaged 3.67 million viewers and a 1.0 key demo rating, nipping the 3.03 million viewers and 0.9 key demo rating for CBS' coverage of the event.
 
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.