Here is a link to Mediabase. You have to be a member to log in. I am able to get the charts via a back door that I kept handy.
It apparently monitors the airplay for several radio stations nationwide in many formats -- rock, adult contemporary, classic rock to name a few.
Check the FAQ link too. It may help and there are some phone numbers to call if anyone is interested.
Apparently they monitor or index a little over 1520 radio stations.
No, it is by no means the industry standard. I believe that is Radio and Records.
http://www.mediabase.com/WebLogon/WebLogon.asp
Bugsy