Top volumes on aggregate

Hello All,

            I have been trying to see if there is a way to get TOP IO volumes for specific aggregate via CLI without perfstat. Looking at the link it appears its possible. Not sure if we need to enable something for this. Its failing currently with error counter does not exist. Checking if any one where able to get this. 

https://docs.netapp.com/ontap-9/index.jsp?topic=%2Fcom.netapp.doc.dot-cm-cmpr-910%2FTOC__statistics__volume.html&lang=en

This is on 9.1

statistics vol show  -aggregate aggr1

Error: command failed: Filter data contains a counter that does not exist:

       "parent_aggr".