Fast National ratings for Friday, April 20, 2012.
 
Airing three hours of repeats, CBS still won Friday night overall, while "What Would You Do?" and "Grimm" helped ABC and NBC split the night among young viewers, despite week-to-week declines.
 
This week's random "Fringe" fluctuation was "up," though that might be caused by the more legitimate growth for its "Finder" lead-in. Meanwhile, The CW's Friday dramas returned after a few weeks off, with "Supernatural" dropping and "Nikita" remaining flat.
 
Among adults 18-49, both ABC and NBC averaged a 1.2 rating for Friday night, tops in the key demographic. FOX was a close second with a 1.1 rating, followed by CBS' 0.9 rating and the 0.5 rating for The CW.
 
Overall, though, CBS averaged an estimated 5.42 million viewers and a 3.6/6 for Friday primetime. NBC was second with 4.82 million viewers and a 3.2/6, beating ABC's 3.0/5 and 4.52 million viewers. FOX finished fourth with 3.65 million viewers and a 2.4/4. The CW averaged 1.49 million viewers and a 0.5 key demo rating.
 
8 p.m. - ABC's repeat of "Shark Tank" won the 8 p.m. hour overall with 5.05 million viewers and tied for the lead with a 1.2 rating among adults 18-49.  FOX's "The Finder" got a solid bump to 4.21 million viewers and a 1.2 key demo rating, its best Friday numbers to date. A repeat of "Who Do You Think You Are?" averaged 4.19 million viewers and a 0.8 key demo rating, compared to the 3.9 million viewers and 0.9 key demo rating for CBS' repeats of "Mike & Molly" and "Rules of Engagement." The CW's "Nikita" averaged just under 1.5 million viewers, up from its last original airing, and stayed in place with a 0.4 key demo rating.
 
9 p.m. - CBS' repeat of "CSI: NY" averaged 6.17 million viewers to win the 9 p.m. hour, but finished fourth with a 0.8 rating among adults 18-49. NBC's "Grimm" was down from last week, but still finished second overall with 4.46 million viewers and tied for the hour in the key demo with a 1.3 rating. "Primetime: What Would You Do?" delivered 4.38 million viewers and a 1.3 key demo rating for ABC. "Fringe" averaged 3.09 million viewers and a 1.0 key demo rating for FOX. The CW's "Supernatural" was on the low side with 1.48 million viewers and a 0.6 key demo rating.
 
10 p.m. - A "Blue Bloods" repeat won the 10 p.m. hour overall for CBS with 6.18 million viewers, coming in third with a 0.8 rating among adults 18-49. NBC's "Dateline" averaged 5.81 million viewers and a 1.4 key demo rating to beat the 4.14 million and 1.3 key demo rating for ABC's "20/20."
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.