The reporting in RoboHelp Server gives you reports on:
Unanswered questions
Frequently asked questions
Areas requiring help
Frequently viewed content
Usage Statistics * (This sounds like what you're looking for)
Question Trends
Help System Errors
I recommend that you check out this excellent article by John
Daigle. It was written for RH Server v6 but mostly everything is
the same for v7.
http://www.adobe.com/devnet/robohelp/articles/rhserver.html