How to determine a current market average rate of return...

[Scott Kelly]

In a book I'm reading, and example was given thus...

"If the current market for a type or property required a 9% return on the capital invested..."

My question is how does one determine the current market "required" or expected, or average or fair cash on cash rate of return on a particular type of property in a specific area?

I can't seem to find this information anywhere.

Is there available data on this? Or is this an educated guestimate made by brokers? I think it would be great information to have in order to set a fair market baseline when looking for income properties.

Thanks.