Fast National ratings for Tuesday, April 21, 2009.

Thanks to a typically robust episode of "American Idol," FOX had no trouble rolling to Tuesday ratings wins in all key measures. Meanwhile, a special Tuesday tryout for "The Unusuals" probably did little to improv e the show's hopes for renewal.

Among adults 18-49, FOX averaged a 6.0 rating, comfortably beating the 3.4 rating for NBC in the key demographic. CBS was third with a 2.4 rating, followed by the 1.9 rating for ABC and The CW's 1.0 rating.

Overall, FOX averaged an estimated 16.88 million viewers in primetime to go with a 9.9 rating/15 share. CBS was well back in second with a 6.8/11, beating the 5.6/9 for NBC and ABC's 5.4/9. The CW was fifth with a 1.6/2.

"American Idol" won the 8 p.m. hour for FOX with a 13.6/22, though the show's 8.0 demo rating was on the low side (for "Idol"). NBC was second with a 5.4/9 first hour for "Biggest Loser: Couples." CBS took third with repeats of "Big Bang Theory" and "Two and a Half Men." ABC's "According to Jim" was fourth, with a pair of new episodes. The CW's "Reaper" was fifth with a 1.6/3.

[Note: The CW had preemptions for sports in several major markets including Chicago and St. Louis. That would explain at least a slight artificial ratings boost for "Reaper."]

ABC grabbed first at 9 p.m. with a 9.4/14 for the "Dancing with the Stars" results show. A CBS repeat of "NCIS" was a solid second. NBC's "Biggest Loser: Couples" was third with a 6.4/10 and won the hour in the 18-49 demo. FOX's "Fringe," aided with only a couple minutes of "Idol" overrun, was fourth with a 6.3/9. The CW's "90210" had a 1.6/2.

A repeat of "The Mentalist" did an 8.1/14 to win the 10 p.m. hour. NBC took second with a "Law & Order: Special Victims Unit" repeat. ABC put "The Unusuals" on a special night and it did a 4.2/7, plummeting from its lead-in. 

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