How to find out what rental rates were in years past?

[Taylor Green]

Hi,

I am wondering how I could find out what rental rates were for a home or an area in past years? I am interested in learning because I wanted to see how much actual rents dropped in different areas during the market crash a few years back. 

I have looked on websites like rent-o-meter and didn't see an option for this. Is there a website that has this information? Would real estate agents have access to something like this?

Thanks.

Taylor