If you navigate to DMI performance details (found in 12.4 from Menu -> Diagnostics -> DMI Performance -> DMI performance details tab), you get a list of all reports loaded from newest first. This list doesn't give you the count of each report, but you can add hit count as a metric and remove hit time to aggregate the counts. There is not a way to explicitly see which reports have not been generated. Comparing the results from this over the last 30 or 365 days against a list of your DMIs should allow you to see which haven't been hit, though.
Hope this helps!
You can also load report:
"DMI query performance by report name" which shows every query
executed on your system.
It is designed to check the
impact of the DMI on your system. So, it shows execution of the queries rather
But you can edit the last
section and add user name which is not available in “DMI performance details” report.