Fast National ratings for Thursday, January 12, 2012.
 
A huge 2012 premiere for "The Big Bang Theory" and a better-than-expected series launch for "Rob" helped carry CBS to easy wins on Thursday night.
 
Meanwhile, NBC got a disappointing season premiere for "30 Rock" and an even-more-dismal time slot premiere for "The Firm," which probably isn't long for this world. Also in instant trouble is FOX's "Bones" semi-spinoff "The Finder," which failed to find an audience in its first entry.
 
Among adults 18-49, CBS averaged a 3.5 rating for the night, topping ABC's 2.8 rating in the key demographic. FOX was third with a 2.0 rating, followed by NBC's 1.8 rating and The CW's 1.0 key demo rating.
 
Overall, CBS averaged an estimated 14.28 million viewers and an 8.6 rating/13 share for Thursday night. ABC was second with a 5.1/8 and 8.14 million viewers, holding off FOX's 4.3/7 and 7.04 million viewers. There was a big drop to fourth place NBC's 4.55 million and 2.9/5, far ahead of The CW's 1.5/2 and 2.43 million viewers.
 
8 p.m. - "The Big Bang Theory" (15.93 million and a 5.2 key demo) and the series premiere of "Rob" (13.48 million and a 4.1 key demo rating) gave CBS plenty of reasons to smile in the 8 p.m. hour. FOX was a distant second with 8.63 million viewers and a 2.4 rating among adults 18-49 for a new "Bones." ABC's "Wipeout" was third with 7.125 million viewers and a 2.2 key demo rating. On NBC, "30 Rock" returned from a long absence with 4.57 million viewers and a 1.8 rating among adults 18-49 and led into 4.1 million viewers and a 1.9 key demo rating for "Parks & Recreation." The CW's "The Vampire Diaries" averaged 2.81 million viewers and a 1.2 key demo rating, both down from last week.
 
9 p.m. - CBS had a strong week for "Person of Interest," which averaged 14.73 million viewers to win the 9 p.m. hour, coming in second with a 3.2 rating among adults 18-49. ABC's "Grey's Anatomy" slipped from last week's return with 10.59 million viewers and an hour-winning 3.8 key demo rating. FOX's "The Finder" averaged 5.45 million viewers and a 1.7 key demo rating, which probably won't make the network pleased. NBC's "The Office" (5.865 million and a 2.9 key rating) and "Up All Night" (4.28 million viewers and a 2.0 key demo) were third in the demo, but fourth overall. Despite a drop for its lead-in, "The Secret Circle" was steady from last week with 2.055 million viewers and a 0.8 key demo rating. 
 
10 p.m. - "The Mentalist" ruled the 10 p.m. hour with 13.395 million viewers and a 2.7 rating among adults 18-49. ABC's "Private Practice" averaged 6.7 million viewers and a 2.4 key demo for second. NBC got a less-than-"Prime Suspect" 4.24 million viewers and a 1.0 key demo rating for "The Firm." 
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.