"American Idol" wrapped its eighth season Wednesday with the lowest rating ever in the 18-49 demographic for an "Idol" finale, even as the series touted its largest margin of victory yet over competitors this season.

The two-hour-plus Wednesday extravaganza featuring performances by KISS, the surviving members of Queen, Rod Stewart, Cyndi Lauper and Steve Martin, posted 28.8 million viewers and a 10.0 rating in adults 18-49, according to estimates. It peaked at 34 million viewers in the final half-hour countdown to the upset victory by Kris Allen.

Those would be astonishing numbers for any other series. But for the juggernaut "Idol," they are only good enough for last place in the demo among its finales, behind the first season's ender when an average of 23 million viewers (10.8/30 in 18-49) tuned in to see Kelly Clarkson crowned as the first American Idol. It was down 12% from last year's finale among 18-49 and 9% in total viewers. The results show finale was the second-lowest among total viewers, since the show's edition, which ran in the summer, finished with a lower number.

That follows similar all-time low marks for the show's final performance show on Tuesday.

Fox notes that this season "American Idol" has dominated competition by a wide margin of victory than ever. "Idol" finished the season 72% ahead of the No. 2 entertainment program in the adult demo (ABC's “Desperate Housewives”). The Tuesday and Wednesday "Idol" editions have ranked as the No. 1 and No. 2 shows for the past six consecutive seasons, the most consecutive No. 1 rankings for any broadcast network program since the start of Nielsen's continuous adult demo measurement more than 20 years ago.