Most listings are in the $30's per square foot per year. The Washington D.C. region is going through a an increase in rates. In the last 3 months, the median rate rose $2 per sqft per year. That's a 6% increase in rent.
In the last 90 days, 1195 listings have been listed, so you'll want to check back regularly for new listings. About 2% of the office spaces in the Washington D.C. are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 3,050 sqft, there are still 0 spaces below 2,000 sqft. Most buildings in this market are around 4 stories. Most buildings in this market were built in 1986 and are Class A.