Fast National ratings for Thursday, May 19, 2011.
NBC got big demo numbers for its "Office" season finale, while the two-hour finale of "The Mentalist" brought viewers to CBS, but there was no stopping "American Idol," which carried FOX to yet another Thursday ratings win.
Among adults 18-49, FOX averaged a 4.7 rating for the night, far ahead of CBS' 2.8 rating in the key demographic. ABC's 2.5 rating and the 2.4 rating for NBC followed. The CW, airing a repeat of last week's "Smallville" finale, averaged a 0.5 rating.
Overall, FOX averaged an estimated 15.62 million viewers and a 9.1 rating/15 share for the night. CBS was a solid second with a 7.7/12 and 12.49 million viewers. There was another big drop to ABC's 5.0/8 and 7.54 million viewers and then to NBC's 2.9/5 and 4.66 million viewers. The CW's 0.8/1 and 1.32 million viewers lagged.
8 p.m. - "American Idol" led the 8 p.m. hour for FOX with 21.19 million viewers and a  6.2 rating among adults 18-49 for the season's final Thursday episode. CBS was second with "The Big Bang Theory" (11.12 million and a 3.5 demo) and "Rules of Engagement" (8.795 million and a 2.5 demo rating). ABC's "Wipeout" averaged 5.59 million viewers and a 1.7 demo rating, easily beating the 2.92 million viewers for a pair of "Office" repeats on NBC. The CW's "Smallville" trailed with 1.29 million viewers.

9 p.m. - Things got competitive in the 9 p.m. hour, with CBS' "The Mentalist" winning overall with 12.67 million viewers, but finishing a distant fourth with a 2.4 demo rating. "Bones" was second overall for FOX with 10.045 million viewers, but third in the key demo with a 3.2 rating. ABC's "Grey's Anatomy" finale was third in viewers with 9.58 million, but second with a 3.4 key demo rating. That meant that even though "The Office" was a distant fourth with 7.07 million viewers, it actually won the hour among adults 18-49 with a 3.8 demo rating. The CW was fifth with 1.35 million viewers for the end of the "Smallville" finale.
10 p.m. - "The Mentalist" improved to 14.84 million viewers and a  3.0 demo rating to rule the 10 p.m. hour for CBS. ABC's "Private Practice" averaged 7.47 million viewers and a 2.5 demo rating for second. NBC's two-episode "Parks and Recreation" season-ender averaged 3.98 million viewers and a 2.2 demo rating for third.
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.
A long-time member of the TCA Board and a longer-time blogger of "American Idol," Dan Fienberg writes about TV, except for when he writes about movies or sometimes writes about the Red Sox. But never music. He would sound stupid talking about music.