Most listings are in the $10's per square foot per year. The Delaware region is experiencing a decline in rates. In the last 3 months, the median rate decreased $8 per sqft per year. That's a 35% decrease in rent.
In the last 90 days, 2 listings have been listed, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. About 400% of the available space in the Delaware 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,390 sqft. Most properties in this area are close to 2 floors. Most buildings in this market were built in 1950 and are Class C.