Server Administrator API - totalUsers not returned

Discussion created by imxxx0212 on Oct 8, 2012
Latest reply on Dec 9, 2013 by tgdang-esrisa-esridist
According to the server admin API issuing an HTTP GET request to [server]/arcgis/admin/security/users shall return the total number of users in the user store. 

e.g. {
  "totalUsers": <number> 

However, I've tested this out (using the Administrator directory) and only receive this as a response: {"isReadOnly":false}.

Am I doing something wrong?