Fast National ratings for Tuesday, July 31, 2012.
 
With two Michael Phelps races and a big win for the US women gymnasts, it's no wonder that Tuesday night's Olympics coverage hit the week's biggest numbers for NBC.
 
Among adults 18-49, NBC averaged a 12.2 rating, just a wee bit ahead of second place CBS' 1.0 rating in the key demographic. FOX averaged a 0.9 key demo rating, while ABC posted a 0.6 key demo rating. The CW's 0.2 key demo rating trailed.
 
Overall, NBC averaged an estimated 37.49 million viewers and a 21.1 rating/33 share for Tuesday primetime. CBS was a rather distant second with a 3.7/6 and 5.44 million, still comfortably ahead of the 1.7/3 and 2.56 million viewers for ABC. FOX's 1.5/2 and 2.25 million viewers beat the 0.4/1 and 666,000 viewers for The CW.
 
8 p.m. - Predictably, NBC started primetime in first with 29.77 million viewers and a 9.0 rating among adults 18-49 for Olympics coverage. CBS' repeat of "NCIS" was second with 6.78 million viewers and a 1.0 key demo rating. ABC's repeats of "The Middle" and "Last Man Standing" averaged 2.52 million viewers and a 0.6 key demo rating, compared to the 2.33 million viewers and 1.0 key demo rating for FOX's "MasterChef" repeat. The CW's repeat of "Hart of Dixie" averaged 781,000 viewers and a 0.2 key demo rating.
 
9 p.m. - The Olympics coverage rose to 40.48 million viewers and a 13.3 rating among adults 18-49 for NBC. CBS' "NCIS: Los Angeles" repeat averaged 5.19 million viewers and a 1.0 key demo rating for second. ABC's "Wipeout" repeat averaged 2.37 million viewers and a 0.7 key demo rating compared to FOX's 2.17 million viewers and a 0.9 key demo rating for a repeat of "Hell's Kitchen." The CW's new "The L.A. Complex" averaged 550,000 viewers (up from last week!) and a 0.2 key demo rating (and a "0" key demo share). 
 
10 p.m. - NBC's final hour of Olympics coverage averaged 42.21 million viewers and a whopping 14.2 rating among adults 18-49. CBS was a distant second with 4.35 million viewers and a 0.9 key demo rating for a repeat of "Person of Interest." ABC's "NY Med" took a big drop from last week, finishing third with 2.8 million viewers and a 0.6 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.
Dan-feinberg-med
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.