CRM 4.0 Toget the details of emails sent by workflows every month from DB side for a report

My requirement is that i need to prepare a report in which i have to show details and count of all emails sent/triggered by workflows(there are so many) from database. Here we need to take a note that we cannot use asyncoperationbase table since we cleaing it up every month

I need a table name from where we can get the workflow and email relation.

please advise me on this.