[otrs] generating report of standard responses for tickets

Hello there, We are very happy users of OTRS, but we would like to build a report that shows us how popular our "standard responses" are. We are capable of writing SQL queries to get the data out, but I don't see anywhere where we can get the standard response ID that was used to generate a particular email. Does anybody know if this data exists in the database somewhere already, or should I go ahead and patch OTRS itself to store the responseID on the "article" or "ticket" tables? Thanks! Billy