Jay Leno's Tonight Show drew a 1.1 adults 18-49 rating last week (May 3-7), the same rating as Conan O'Brien's Tonight Show in the tenth week of each show's run. There has been little difference between the two show's ratings trends since week 5 of their run's.
I need to try and figure out how to convey this well in the chart, but readers should note that 10 weeks into "Conan (2009-10)" was the first week of August, 2009, the absolute nadir of the broadcast TV year, but 10 weeks into "Leno (2010-)", is still during the main broadcast season.
David Letterman's Late Show moved up a tenth of a point in the adults 18-49 ratings vs. the previous week, but was again beaten by the Tonight Show as it has been each week since Jay returned.
Conan/Letterman (2009-10) week 1 ended 6/5/09. Leno/Letterman (2010-) week 1 ended 3/5/10.
The Conan/Letterman(2009-10) ratings do not include the final week the Tonight Show was in repeats prior to the Winter Olympics.
For historical reference, here are last season’s season-to-date averages through May 8, 2009:
11:35 p.m. ET
NBC “Tonight,” 1.4/6
CBS “Late Show,” 1.1/4
ABC “Nightline,” 1.1/4