nielsen ratings
(fast national numbers for thursday, april 21, 2011)

Here are the highlights of the 16 ad-sustained programs that aired in primetime on the broadcast networks last night:

FOX (15.36 million viewers, #1; adults 18-49: 4.4, #1) as usual was the network to beat on Thursday with new episodes of "American Idol" (19.62 million viewers, #1; adults 18-49: 5.6, #1) and "Bones" (11.10 million viewers, #2; adults 18-49: 3.2, #3).

NBC (4.49 million viewers, #3; adults 18-49: 2.1, #2) then claimed the silver with new episodes of "Community" (3.30 million viewers, #12; adults 18-49: 1.5, #T9), "The Paul Reiser Show" (2.54 million viewers, #15; adults 18-49: 0.9, #14), "The Office" (6.80 million viewers, #6; adults 18-49: 3.3, #2), "Parks & Recreation" (5.09 million viewers, #8; adults 18-49: 2.5, #4) and a one-hour "30 Rock" (4.62 million viewers, #10; adults 18-49: 2.2, #5).

Next up was CBS (8.55 million viewers, #2; adults 18-49: 1.8, #3) with repeats of "The Big Bang Theory" (7.04 million viewers, #5; adults 18-49: 1.8, #7), "Rules of Engagement" (5.51 million viewers, #7; adults 18-49: 1.5, #T9), "CSI: Crime Scene Investigation" (8.40 million viewers, #4; adults 18-49: 1.6, #8) and "The Mentalist" (10.96 million viewers, #3; adults 18-49: 2.1, #6).

ABC (3.77 million viewers, #4; adults 18-49: 1.1, #4) likewise offered up its all-repeat lineup of "Wipeout" (4.74 million viewers, #9; adults 18-49: 1.3, #11), "Grey's Anatomy" (3.86 million viewers, #11; adults 18-49: 1.2, #12) and "Private Practice" (2.73 million viewers, #13; adults 18-49: 0.8, #T15).

And finally, new episodes of "The Vampire Diaries" (2.65 million viewers, #14; adults 18-49: 1.1, #13) and "Nikita" (1.94 million viewers, #16; adults 18-49: 0.8, #T15) on The CW (2.30 million viewers, #5; adults 18-49: 0.9, #5) rounded out the night.

Week-to-week changes (adults 18-49): Community (7.10%), 30 Rock (0.00%), Nikita (0.00%), Parks & Recreation (-3.80%), American Idol (-8.20%), The Vampire Diaries (-8.30%), Bones (-13.50%), The Office (-15.40%), The Paul Reiser Show (-18.20%).

In late-night metered market ratings (via NBC's press release):

In Nielsen's 56 metered markets (the Nashville market is delayed), household results were: "The Tonight Show with Jay Leno," 2.0/5 with an encore telecast delayed by a preview of "The Voice"; CBS's "Late Show with David Letterman," 2.6/6 with an encore; and ABC's combo of "Nightline," 2.7/6; and "Jimmy Kimmel Live," 1.3/4.

In the 25 markets with Local People Meters, adult 18-49 results were: "The Tonight Show with Jay Leno," 0.9/4 with an encore delayed by "Voice" preview; "Late Show," 0.6/3 with an encore; "Nightline," 0.7/3; and "Jimmy Kimmel Live," 0.4/2.

At 12:35 a.m., "Late Night with Jimmy Fallon" (1.2/4 in metered-market households with an encore delayed by "Voice" preview) trailed CBS's on-time first-run "Late Late Show with Craig Ferguson" (1.5/5). In the 25 markets with Local People Meters, "Late Night" (0.5/2 in 18-49 with an encore delayed by "Voice" preview) topped "Late Late Show" (0.4/2).

At 1:35 a.m., Last Call with Carson Daly" averaged a 0.7/3 with an encore delayed by "Voice" preview in metered-market households and a 0.4/3 in adults 18-49 in the 25 markets with local people meters.

Here are the highlights of the 15 ad-sustained programs that aired in primetime on the broadcast networks one year ago (4/22/10):

CBS (13.29 million viewers, #1; adults 18-49: 3.1, #1) once again snagged the top spot on Thursday thanks to new episodes of "Survivor: Heroes vs. Villains" (11.78 million viewers, #3; adults 18-49: 3.6, #1), "CSI: Crime Scene Investigation" (13.32 million viewers, #2; adults 18-49: 2.9, #4) and "The Mentalist" (14.78 million viewers, #1; adults 18-49: 3.0, #3).

Second place then went to FOX (7.36 million viewers, #2; adults 18-49: 2.3, #2) with fresh installments of "Bones" (8.84 million viewers, #4; adults 18-49: 2.5, #T5) and "Fringe" (5.89 million viewers, #7; adults 18-49: 2.1, #8).

Next up was NBC (4.72 million viewers, #4; adults 18-49: 2.2, #3) and its mix of "Community" (3.91 million viewers, #13; adults 18-49: 1.7, #11), "30 Rock" (4.22 million viewers, #12; adults 18-49: 1.9, #T9), "The Office" (6.41 million viewers, #6; adults 18-49: 3.3, #2), another "30 Rock" (5.18 million viewers, #9; adults 18-49: 2.5, #T5) and "The Marriage Ref" (4.30 million viewers, #11; adults 18-49: 1.9, #T9).

Meanwhile, ABC (5.78 million viewers, #3; adults 18-49: 1.7, #4) offered up new episodes of "FlashForward" (5.56 million viewers, #8; adults 18-49: 1.6, #12), "Private Practice" (7.41 million viewers, #5; adults 18-49: 2.3, #7) and a repeat of "Grey's Anatomy" (4.38 million viewers, #10; adults 18-49: 1.4, #14).

And finally, new episodes of "The Vampire Diaries" (3.27 million viewers, #14; adults 18-49: 1.5, #13) and "Supernatural" (2.69 million viewers, #15; adults 18-49: 1.3, #15) on The CW (2.98 million viewers, #5; adults 18-49: 1.4, #5) rounded out the evening.

Source: Nielsen Media Research