Fast National ratings for Tuesday, August 12, 2014.

"America's Got Talent" led NBC to its normal Tuesday wins, but ABC got a bump from the hastily scheduled "20/20: The Life and Death of Robin Williams" special.

The Robin Williams tribute came in far ahead of the summer's earlier "20/20" special, a June hour dedicated to Hillary Clinton.

Other Wednesday notables saw "Extreme Weight Loss" stay flat and "Food Fighters" slip a hair in the key demo from last week.

On to the numbers...

Among adults 18-49, NBC averaged a 1.7 rating for Tuesday night, tops in the key demographic and comfortably ahead of the 1.3 key demo rating for ABC. CBS was third with a 0.9 key demo rating, followed by FOX's 0.6 key demo rating and the 0.3 key demo rating for The CW.

Overall, NBC averaged an estimated 7.84 million viewers and a 4.6 rating/8 share for Tuesday primetime, beating the 6.34 million viewers and 4.1/7 for CBS. ABC was third with 5.05 million viewers and a 3.4/6, far ahead of the 1.43 million viewers and 1.0/2 for FOX. The CW averaged 824,000 viewers and a   0.5/1 for the night.

8 p.m. - A repeat of "NCIS" led the 8 p.m. hour overall with 8.07 million viewers for CBS, coming in second with a 1.0 rating among adults 18-49. NBC's "Food Fighters" was second with 4.41 million viewers and won the hour with a 1.1 key demo rating, just ahead of the 3.82 million viewers and 1.0 key demo rating for ABC's "Extreme Weight Loss." FOX's repeats of "Family Guy" and "Brooklyn Nine-Nine" averaged 1.65 million viewers and a 0.7 key demo rating, well in front of the 804,000 viewers and 0.2 key demo rating for The CW's "Arrow" repeat.

9 p.m. - "America's Got Talent" led the 9 p.m. hour with 9.39 million viewers and a 2.0 rating among adults 18-49 for NBC. CBS' "NCIS: Los Angeles" averaged 6.11 million viewers for second and a 0.9 key demo rating for third. ABC's "Extreme Weight Loss" was third with 4.14 million viewers and second with a 1.3 key demo rating. FOX's repeats of "New Girl" and "The Mindy Project" averaged only 1.21 million viewers and a 0.5 key demo rating, not all that much better than the 843,000 viewers and 0.3 key demo rating for The CW's "Supernatural" repeat.

10 p.m. - NBC's "America's Got Talent" closed primetime in first with 9.71 million viewers and a 2.1 rating among adults 18-49. ABC's "20/20: The Life and Death of Robin Williams" averaged 7.19 million viewers and a 1.7 key demo rating in second. CBS' "Person of Interest" repeat averaged 4.845 million viewers and a 0.8 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.