Cap rate info by area/county

[Jason Cosner]

I am dealing with an eminent domain of a piece of commercial property. The special tax district trying to purchase the property, is implying that the area I am in, averages a 7.5 cap rate for commercial. The property is located outside of a major city that you can’t buy anything investment wise near that cap rate (lucky to get 4%) in my area. How can I find info on recent sales/cap rate average for a specific area, or even better, a county?