For the fourth consecutive day, NBC Nightly News was #1 in total viewers, topping ABC and CBS. But the CBS Evening News with Katie Couric continues to attract more viewers in the prized 25-54 demographic than NBC and ABC. Only 110,000 demo viewers separate the #1 demo net (CBS) from #3 (ABC).

Here are the numbers for Thursday, Sept. 21:

Total viewers: NBC: 8,050,000 / ABC: 7,710,000 / CBS: 7,250,000

25-54 demo: CBS: 2,590,000 / NBC: 2,500,000 / ABC: 2,480,000

> Update: 2:07pm: A self-described "armchair analyst" has a theory: "I'll tell you why CBS is coming in first in the demo. They're getting the viewers they had their eyes on going into this -- the viewers who are getting news feeds on their computers and mobile devices all day, and really don't need a review of the headlines on TV at night. CBS is providing an analysis of the news which is meaningful to the demo viewers who have seen text headlines and maybe a picture or two all day. NBC is getting the older viewers who may prefer the traditional approach and don't know the news until they see it at 6:30."