The typical asking rate per listing is in the $30's per square foot per year. The Washington D.C. region is going through a a boost in rates. In the last 3 months, the median rate increased $32 per sqft per year.
In the last 90 days, 1195 listings have been made available, so you'll want to check back regularly for new listings. About 167% of the available leases in the Washington D.C. are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
Even though the median size is 2,820 sqft, there are still 0 leases below 2,000 sqft. Most properties in this region are close to 4 floors. Most buildings in this market were built in 1986 and are Class A.