$ ./bin/mail volume
+==============+============+
| User         | Unfiltered |
+==============+============+
| admin        | 136        |
| dog          | 31         |
| epriestley   | 24         |
| ducksey      | 18         |
| saurus       | 8          |
| example-list | 7          |
| squeakybirdo | 3          |
| nnn          | 3          |
| facebooker   | 2          |
+==============+============+

Mail sent in the last 30 days.
"Unfiltered" is raw volume before preferences were applied.