Fast National ratings for Thursday, July 19, 2012.
 
It was a "big" night for CBS, as repeats of "The Big Bang Theory" and a new episode of "Big Brother" helped the network dominate the early evening and roll to a comfortable Thursday win in all key measures.
 
Among adults 18-49, CBS averaged a 1.8 rating, easily tops in the key demographic. ABC was second with a 1.3 rating, followed by FOX's 1.1 key demo rating. NBC averaged a 0.6 key demo rating, while The CW had a 0.2 rating.
 
Overall, CBS averaged an estimated 6.53 million viewers and a 4.1 rating/7 share for Thursday primetime, far ahead of the 3.1/5 and 4.84 million viewers for ABC. NBC averaged an 2.0/3 and 2.732 million viewers, nipping FOX's 1.7/3 and 2.729 million viewers. The CW averaged 637,000 viewers and a 0.4/1.
 
[Univision averaged 3.79 million viewers and a 1.5 rating among adults 18-49 for Thursday night.]
 
8 p.m. - Two repeats of "The Big Bang Theory" delivered Thursday's best numbers with 8.15 million viewers and a 2.3 rating among adults 18-49 for CBS. ABC's "Duets" was second overall with 4.48 million viewers and third in the key demo with a 0.9 rating. FOX's "Take Me Out" averaged 3.13 million viewers for third and a 1.2 key demo rating for second. On NBC, repeats of "The Office" and "Parks and Recreation" averaged 1.82 million viewers and a 0.6 key demo rating, compared to the 740,000 viewers and 0.3 key demo rating for The CW's repeat of "The Vampire Diaries."
 
9 p.m. - The season's first Thursday elimination episode of "Big Brother" averaged 6.26 million viewers and a 2.2 rating among adults 18-49 to lead the 9 p.m. hour for CBS, though it was down from last week's premiere. ABC's "Wipeout" averaged 5.04 million viewers and a 1.6 key demo rating for second, though it was also down from last Thursday. NBC's "Saving Hope" averaged 2.99 million viewers for third and a 0.5 key demo rating for fourth. FOX was third in the key demo with a 1.1 rating and fourth overall with 2.33 million viewers for two repeats of "New Girl." On The CW, an encore of "L.A. Complex" averaged 533,000 viewers and a 0.2 key demo rating.
 
10 p.m. - CBS stayed first overall for the 10 p.m. hour with 5.18 million viewers for a repeat of "Person of Interest," finishing second with a 1.0 rating among adults 18-49. ABC's "Rookie Blue" was up week-to-week with 4.99 million viewers and a 1.4 key demo rating. NBC's "Rock Center" was way down from last week with 3.39 million viewers and a 0.7 key demo 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.