I need some information on the size of the restaurant advertising
market in the United States.  Specifically...

1.  Which are the largest 20 metropolitan areas in the US, by population?  (easy!)

2.  How many restaurants are in each of these metro areas? (harder!)

3.  How much do these restaurants collectively spend on advertising in
a year?  (hardest!)

The third question is the most important.  I'd love to see this data
broken out by actual spending by metro area (e.g., in NYC, there are
20,000 restaurants, and they spent $X on advertising in 2004).

In a pinch, I'll settle for national averages applied to each local
market (e.g., in all metro areas, restaurants spent $15 billion on
advertising in the US in 2004.  The 20,000 restaurants in NYC account
for Y% of this.)  If you do apply national averages, please use
multiple corroborating sources.

I've seen reports that the local advertising market, across all
business types in the US, is about $20 billion / year.  Restaurants
represent a subset of this.