Virtual server statistics return 0 using iControlRest API

Hi All

I use the iControlRest API to get relevant data of Virtual server but all the return values are 0. I'm pretty sure VS statistics are greater than 0. Why? Please help me!

curl -k -u admin:admin -X GET "https://132.228.198.244/mgmt/tm/ltm/virtual/WLSJFXXT-LB-VS-172.16.18.43-9091/stats"