I got the most recent rental vacancy rates for major metro areas at the Census site.
Among all the metropolitan areas listed the median is 7.8%.
First the markets with the lowest and highest vacancy rates :
Lowest 5 :
| Bridgeport-Stamford-Norwalk, CT | 2.2 |
| San Jose-Sunnyvale-Santa Clara, CA | 2.8 |
| Oxnard-Thousand Oaks-Ventura, CA | 3.5 |
| San Francisco-Oakland-Fremont, CA | 3.5 |
| Toledo, OH | 3.6 |
Highest 5 :
| Dayton, OH | 18.8 |
| Milwaukee-Waukesha-West Allis, WI | 17.0 |
| Richmond, VA | 15.4 |
| Las Vegas-Paradise, NV | 15.3 |
| Orlando, FL | 15.0 |
Here is the full list for Q4 of 2012 :
| Metropolitan Statistical Area | |
| Akron, OH | 9.8 |
| Albany-Schenectady-Troy, NY | 6.2 |
| Alburquerque, NM | 7.1 |
| Allentown-Bethlehem-Easton, PA-NJ | 9.3 |
| Atlanta-Sandy Springs-Marietta, GA | 12.8 |
| Austin-Round Rock, TX | 13.1 |
| Bakersfield, CA | 5.0 |
| Baltimore-Towson, MD | 7.5 |
| Baton Rouge, lA | 6.5 |
| Birmingham-Hoover, AL | 12.2 |
| Boston-Cambridge-Quincy, MA-NH | 7.2 |
| Bridgeport-Stamford-Norwalk, CT | 2.2 |
| Buffalo-Cheektowaga-Tonawanda, NY | 10.3 |
| Charlotte-Gastonia-Concord, NC-SC | 6.3 |
| Chicago-Naperville-Joliet, IL | 9.8 |
| Cincinnati-Middletown, OH-KY-IN | 9.0 |
| Cleveland-Elyria-Mentor, OH | 10.7 |
| Columbia, SC | 7.8 |
| Columbus, OH | 6.5 |
| Dallas-Ft. Worth-Arlington, TX | 11.3 |
| Dayton, OH | 18.8 |
| Denver-Aurora, CO | 4.7 |
| Detroit-Warren-Livonia, MI | 10.4 |
| El Paso, TX | 9.5 |
| Fresno, CA | 8.8 |
| Grand Rapids-Wyoming, MI | 6.4 |
| Greensboro-High Point, NC | 8.4 |
| Hartford-West Hartford-East Hartford, CT | 9.6 |
| Honolulu, HI | 4.0 |
| Houston-Baytown-Sugar Land, TX | 10.1 |
| Indianapolis, IN | 11.2 |
| Jacksonville, FL | 9.7 |
| Kansas City, MO-KS | 10.8 |
| Las Vegas-Paradise, NV | 15.3 |
| Los Angeles-Long Beach-Santa Ana, CA | 5.2 |
| Louisville, KY-IN | 10.1 |
| Memphis, TN-AR-MS | 14.8 |
| Miami-Fort Lauderdale-Miami Beach, FL | 7.3 |
| Milwaukee-Waukesha-West Allis, WI | 17.0 |
| Minneapolis-St. Paul-Bloomington, MN-WI | 6.3 |
| Nashville-Davidson-Murfreesboro, TN | 5.1 |
| New Haven-Milford, CT | 9.9 |
| New Orleans-Metairie-Kenner, LA | 12.8 |
| New York-Northern New Jersey--Long Island, NY | 5.9 |
| Oklahoma City, OK | 13.1 |
| Omaha-Council Bluffs, NE-IA | 9.9 |
| Orlando, FL | 15.0 |
| Oxnard-Thousand Oaks-Ventura, CA | 3.5 |
| Philadelphia-Camden-Wilmington, PA | 13.5 |
| Phoenix-Mesa-Scottsdale, AZ | 11.0 |
| Pittsburgh, PA | 5.4 |
| Portland-Vancouver-Beaverton, OR-WA | 5.2 |
| Poughkeepsie-Newburgh-Middletown, NJ | 5.0 |
| Providence-New Bedford-Fall River RI-MA | 6.9 |
| Raleigh-Cary, NC | 7.9 |
| Richmond, VA | 15.4 |
| Riverside-San Bernardino-Ontario, CA | 7.0 |
| Rochester, NY | 4.4 |
| Sacramento-Arden-Arcade-Roseville, CA | 7.5 |
| St. Louis, MO-IL | 12.2 |
| Salt Lake City, UT | 5.6 |
| San Antonio, TX | 7.5 |
| San Diego-Carlsbad-San Marcos | 6.4 |
| San Francisco-Oakland-Fremont, CA | 3.5 |
| San Jose-Sunnyvale-Santa Clara, CA | 2.8 |
| Seattle-Tacoma-Bellevue, WA | 7.7 |
| Springfield, MA. | 5.2 |
| Syracuse, NY | 9.4 |
| Tampa-St. Petersburg-Clearwater, FL | 12.1 |
| Toledo, OH | 3.6 |
| Tucson, AZ | 14.7 |
| Tulsa, OK | 7.0 |
| Virginia Beach-Norfolk-Newport News, VA | 3.7 |
| Washington-Arlington-Alexandria, DC-VA-MD-WV | 7.8 |
| Worcester, MA | 5.7 |
