Thus far this season, O'Brien's Tonight Show has trailed The Late Show with David Letterman by an average of 1.7 million total viewers, or 65%. (For comparison's sake, Leno had a 20% lead over Letterman's show last year.) Among the advertiser-beloved demographic of 18- to 49-year-olds, O'Brien and Letterman have fared about the same--not bad, until you consider that Leno had a 15% lead in that key area.
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