The WSA doesn't actually track it...
probably the best option is to see how many users are logged in...
Go to the CLI, enter "authcache" then "list"
wsa> authcache
Choose the operation you want to perform:
- FLUSHALL - Flush all entries from auth cache
- FLUSHUSER - Flush specific user entry from auth cache
- LIST - List all entries from auth cache
- SEARCH - Search all entries from auth cache
[]> list
List may print a lot of entries. Are you sure? [Y]> y
AD\backadmn@AD
AD\kenst@AD
2 entries in authentication cache