Annual increase: 7.4%
Average monthly rent: $1,473
Vacancy rate: 4.6% (5.7% in 2009)
Average concession: -2%

Rental vacancies are low in Washington, where the federal government has kept employment strong and the economy has performed better than in the rest of the country. Unemployment in the D.C. area hovered just above 6 percent in 2010, about the same from a year earlier, show BLS data. Renters in some areas of Old Town in Alexandria, across the Potomac River from Washington, paid 13.5 percent more in 2010, according to AXIOMetrics. The firm predicts the average rate increase to slow to 5 percent this year.