Advanced Listproc -Statistics
You can get a list of the statistics for all of the non-concealed subscribers to a list, cross-referenced to the number of messages each has sent, with the statistics command.
You can also get a listing for a single specified user
statistics <listname> John@twenty.net
The -all option lists statistics for all list subscribers past and present.
statistics <listname> John@twenty.net | [-all]