The typical asking rate per listing is in the $10's per square foot per year. The Dover region is going through a decrease in rates. In the last 3 months, the median rate decreased $4 per sqft per year. That's a 16% decline in rent.
In the last 90 days, 13 listings have come on the market, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. 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 5,000 sqft, there are still 0 spaces below 2,000 sqft. Most buildings in this area are around 2 floors. Most buildings in this region were built in 1968 and are Class C.