Currently this is going to require some data extractions and manipulation as Breno mentioned. There is no nice out of the box performance view that will tell you this. There is an idea in the very early stages, so getting voting an commenting on what exactly you want to see https://genesyscloud.ideas.aha.io/ideas/ANLS-I-1073
Tou could extract call information, and external contact information, then yes do a count of customer ids/phone numbers etc per day. You could then combine that with either wrap up codes (agent perspective) or customer survey results (customer perspective) for the resolution, to see yes call was resolved but that was on the 3rd call that day etc. We haven't got this down right yet ourselves, so very much just theory crafting from my end.
------------------------------
Anton Vroon
------------------------------