MAC address authentication hits on WLC 9800

[RHNHS16]

Hi All, 

So far I haven't managed to find any results for this after looking online...

Quick overview: we have a 9800 WLC that has some legacy systems still using MAC address device authentication. Unfortunately, it's got a bit out of hand and I would like to clean the list up. - I'm certain there will be old MACs in the list. 

Question:
Can anybody advise if there is a way I can see how many hits (ideally with timestamp) the MACs have so I can filter out and remove the unused addresses from the whitelist? 

Is this isn't a possibility on the WLC GUI or CLI is it a possibility to do this from DNAC (Catalyst Centre)? 

Many thanks!

[marce1000]

   - Perhaps the logs of the DHCP server (configured) could be useful to get that information , 

 M.