Fox News may want to keep an eye on its 5 p.m. show, The Big Story with John Gibson. Lately, CNN's The Situation Room with Wolf Blitzer has been challenging FNC for #1 in the 25-54 demographic category.

For the week of May 8, Gibson drew 146,000 viewers, losing narrowly to Blitzer's 150,000. Just a three percent win, right? Well the week of May 15, CNN beat FNC by 19 percent in the demo, with Gibson averaging 166,000 and Blitzer averaging 198,000. Both shows beat Hardball; the 5 p.m. airing averaged 102,000 demo viewers for the first week and 90,000 for the second.

Among total viewers, Gibson always beats Blitzer handily. Last week, FNC averaged 889,000 and CNN had 591,000. But for advertisers, it's the demo viewers who matter.

CNN only beat FNC for six days out of the past two weeks. (And on Monday, Big Story beat Sit Room by 100,000 demo viewers.) But it's notable for any CNN show's viewership to be anywhere near any FNC show's viewership in the demo...

> Update: On Tuesday, Blitzer averaged 99,000 demo viewers while Gibson had 181,000...