The site of the 2009 National Convention for the National Association of Realtors will be right here in downtown San Diego at the Convention Center.

The San Diego Convention Center was expanded in the late 1990s to encompass a total of about 670,000 square feet.

At the time, that ranked it in the Top 10 convention centers in the United States. Conventions, however, are serious business, and convention centers everywhere have been expanding.

Here are the top convention centers in terms of exhibit space:

1. McCormick Place, Chicago
2. Orange County Convention Center, Orlando
3. Las Vegas Convention Center
4. Georgia World Congress Center, Atlanta
5. New Orleans Morial Convention Center
6. Sands Expo and Convention Center, Las Vegas
7. Dallas Convention Center
8. The Moscone Center, San Francisco
9. Phoenix Convention Center
10. George R. Brown Convention Center, Houston
11. Donald E. Stephens Convention Center, Chicago
12. Jacob K. Javits Convention Center, New York City
13. San Diego Convention Center
14. The Colorado Convention Center, Denver
15. America Center, St. Louis
16. Boston Convention and Exhibition Center
17. Tampa Convention Center
18. Henry B. Gonzalez Convention Center, San Antonio
19. Reno-Sparks Convention Center, Reno/Tahoe
20. Salt Palace Convention Center, Salt Lake City

The San Diego Convention Center has spent over $200,000 on an expansion study, which provides the following projected data:

• $753 million to double the size of the Convention Center to 1.27 million square feet
• $50 million annual cost to pay construction bonds
• $372 million additional annual revenue from conventions
• 6,885 new permanent jobs

The last expansion in the late 1990s created a brouhaha, but it has proven to be good for San Diego, bringing in larger conventions and keeping Comic Con, a home-grown convention that now gets about 150,000 visitors, from having to move to a larger convention center elsewhere in the country.