Annual increase: 6.1%
Average monthly rent: $938
Vacancy rate: 6.7% (8.8% in 2009)
Average concession: -4%
The annual unemployment rate in Wilmington—home to chemicals company DuPont, pharmaceutical giant AstraZeneca, and Gore-Tex maker W.L. Gore & Associates—rose to about 9 percent last year compared with 8.5 percent in 2009, according to estimates using BLS preliminary data. After rental rates rebounded in 2010, AXIOMetrics expects the rate increase to slow to 3.9 percent this year.