The tenth season premiere of aging juggernaut "American Idol" fell 13 percent among total viewers and 18 percent in the ad-coveted demographic of 18-49-year olds, according to preliminary data from Nielsen. The much-hyped two-hour opener, featuring new judges Jennifer Lopez and Steven Tyler, was watched by 26.1 million viewers with a 9.7 in the demo.
Last year's premiere -- which kicked off the final year of Simon Cowell, considered by many observers to be the show's linchpin -- was watched by 29.9 million viewers and averaged an 11.8 demo rating. That was down slightly compared to the 2009 premiere, which averaged 30.4 million viewers and an 11.7 rating in the demo.
"American Idol" has been declining since the 2007 season when the premiere installment attracted a high of 37.4 million viewers with a 15.8 in the demo.
Last night's decline is not entirely surprising given the shows age and this year's makeover. But the premiere most likely benefited from a curiosity factor ratings boost. So the true test of "Idol's" staying power - and Lopez and Tyler's success as judges -- will come as the season wears on.