Routing table hits?
Try
route -neeC
and look at the "Use" column. man route says this is the count of lookups for the route.
I don't know of a way to get this information directly, but it would be relatively straightforward with a set of empty rules in iptables that match up with the rules in the routing table.
FreeBSD:
netstat -rn
Linux:
netstat -rneC
Windows:
I think something can be done via netsh