Most listings are in the $0's per square foot per year. The Dover submarket is experiencing a decline in rates. In the last 3 months, the median rate decreased $15 per sqft per year. That's a 100% decline in rent.
In the last 90 days, 0 listings have come on the market, which means listings are probably leasing quickly. You'll want to be prepared to make an offer immediately. About NaN% of the available leases in the Dover are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around sqft. Most buildings in this market were built in 1934 and are Class C.