I don't know of any ready-made report. Possibly with the old contacts, but if you've converted to the new Contact Manager I don't think so.
 
BTW, I have all our user's workstations set to BCC me. A CC or BCC is the only way to confirm that an email was actually sent. Yes, a PDF is created and copied to the the specified location, but it doesn't tell you the email was sent (sometimes you get an "Email NOT sent" message), and it doesn't show you what address(es) were used. I have them all sent to me so that they are all in one place, but we're a pretty small company. You might want to do it by department or individual as well.