08/13/2010 09:32 am ET Updated May 25, 2011

Leno Ratings: 'Tonight Show' Widens Lead Over Letterman

Jay Leno saw his biggest ratings lead over David Letterman since the week he took back "The Tonight Show."

Variety reports (registration required) that last week (August 2-6), "The Tonight Show" topped "The Late Show" by a whopping 41% among adults 18-49, the entertainment demographic advertisers care most about. Leno averaged 1.29 million A18-49 viewers to Letterman's 914,000. That represents the widest margin between the rival late-night hosts since the week Leno returned to the show.

Among total viewers, Leno averaged 3.85 million for a 31% lead over Letterman (2.83 million).

NBC must be happy, as the advantage is spilling over into the 12:30AM time-slot as well.

The network's "Late Night with Jimmy Fallon" beat CBS' "Late Late Show with Craig Ferguson" by its biggest margins in 20 weeks among total viewers, and 16 weeks among the demo.

In a column last week, Bill O'Reilly mocked Letterman's ratings, saying that the "Late Show" host "gets trounced in the ratings by Fox News Channel every night."