Preliminary Nielsen data from 55 cities where it operates so-called "people meters," set-top boxes that monitor television viewing, shows that a third of all TV sets were tuned into Friday night's debate between Barack Obama and John McCain. Nielsen won't release final data until Monday, but if the trend from the 55 metered markets holds steady, it would mean about 57 million people watched the debate.

The city with the highest percentage of viewers was St. Louis, where 52 percent of the TVs were tuned to the debate, reflecting either an inordinate civic-mindedness or a complete lack of actual lives, take your pick. The lowest was Phoenix, with only about 24 percent, which might mean that they're confident their guy McCain has already won, or that they're sick of him, take your pick again. South Florida was somewhere in the middle, with about 37 percent of the TVs on the debate.

Here's the complete list of Nielsen's metered markets. "Rating" means the percentage of all TV sets that were tuned to the debate; "share" is the percentage of TV sets that were actually in use that were tuned in.