(Reuters) - Broadcast network CBS said on Tuesday it won this season's ratings race among the 18-to-49 age group most prized by advertisers, claiming its first victory in that audience in 21 years.
CBS, a unit of CBS Corp, snatched the title from News Corp-owned Fox, which had dominated the age group for eight straight years until it was hurt this season by a ratings slump for singing competition "American Idol."
CBS rode hits like "The Big Bang Theory" and "2 Broke Girls" and was helped by February's Super Bowl broadcast, which attracted the biggest TV audience of the year. Even without the big game, CBS said it would have been first in the key age group.
The network drew an average of 3.7 million prime time viewers ages 18 to 49, according to Nielsen ratings data through May 19. Although three nights remain in the season, results are unlikely to change significantly.
According to Nielsen, Fox finished second with 3.2 million in the key audience group, followed by Comcast-owned NBC with 3.0 million and Walt Disney Co's ABC with 2.8 million.
All of the networks lost viewers among 18-49 year old demographic, with CBS declining by 3.6 percent, as broadcasters fought competition from cable channels and streaming services like Netflix as well as delayed and mobile viewing that Nielsen does not fully measure.
CBS also dominated ratings based on overall viewers for the 10th time in 11 years, the network said. Total viewers rose 1 percent to 11.9 million, followed by ABC with 7.9 million, Fox with 7.0 million and NBC with 6.96 million.
(Reporting by Lisa Richwine; Editing by Bob Burgdorfer)