Fast National ratings for Thursday, May 8, 2014.

Spring doldrums hit Thursday primetime hard, with big audience drops for most primetime offerings, including CBS' "Big Bang Theory," which had its weakest night in recent memory. Of course, even a historically weak "Big Bang Theory" was still able to lead Thursday in all measures and carry CBS to comfortable primetime wins. 

Among the other shows posting big audience declines on Thursday were "Grey's Anatomy," "Bad Teacher" and "Black Box," while NBC's "American Comedy Awards" was no match for last week's IHeartRadio award show.

On the positive side, FOX's "American Idol" had a slight rebound from last week's Thursday low, while the newly cancelled "Surviving Jack" got a solid bump for what seems to be its series finale. If these numbers hold up, "Surviving Jack" will end the week as FOX's most-watched comedy and tied with "New Girl" in the key demo.

On to the numbers...

Among adults 18-49, CBS averaged a 2.0 rating for Thursday night, easily tops in the key demographic. FOX was second with a 1.5 key demo rating, topping the 1.3 key demo rating for ABC. NBC's 1.0 key demo rating and the 0.6 key demo rating for The CW trailed for the night.

Overall, CBS averaged an estimated 8.78 million viewers and a  5.6 rating/9 share for Thursday primetime. ABC was a distant second with 4.94 million viewers and a 3.5/6, nipping the 3.1/5 and 4.9 million viewers for FOX. NBC was fourth with 3.19 million viewers and a 2.1/4, followed by the 1.54 million viewers and 1.1/2 for The CW.

8 p.m. - CBS cruised to victory in the 8 p.m. hour with "Big Bang Theory" (14.17 million and a 3.7 key demo) and "The Millers" (9.15 million and a 2.0 key demo rating). [Say what you will about "The Millers," but even though its lead-in was down by 0.7 in the key demo over last week's Fast Nationals, the freshman comedy only dropped by 0.1 itself.] There was a steep drop to the 4.21 million viewers and 1.5 key demo rating for FOX's "Hell's Kitchen" and then another drop to the 3.26 million viewers and 0.9 key demo rating for NBC's "Hollywood Game Night." Even ABC's repeat of "Grey's Anatomy" was down with 2.935 million viewers for fourth and a 0.6 key demo rating for fifth, compared to the 1.6 million viewers and 0.7 key demo rating for The CW's "The Vampire Diaries."

9 p.m. - "Grey's Anatomy" may have been down from last week, but it still won the 9 p.m. hour with 7.47 million viewers and a 2.3 rating among adults 18-49. CBS was second with the season finale for "Two and a Half Men" (8.49 million and a 2.1 key demo) and a new "Bad Teacher" (5.84 million and a 1.3 key demo rating). FOX was third with "American Idol" (7.075 million and a 1.6 key demo rating) and the "Surviving Jack" finale (4.1 million and a 1.2 key demo rating). The first hour of the American Comedy Awards averaged 3.05 million viewers and a 1.0 key demo rating on NBC. The CW's "Reign" averaged 1.47 million viewers and a 0.5 key demo rating.

10 p.m. - "Elementary" was down but still led the 10 p.m. hour with 7.5 million viewers and a 1.5 rating among adults 18-49. ABC's "Black Box" continued to fade to black with 4.41 million viewers and a 1.1 key demo rating, at least topping the 3.245 million viewers and 1.0 key demo rating for the American Comedy Awards on NBC.

All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.