Hi there!
This is usually something you can see by enabling statistics. For performance reasons, this is usually off.
On older 7-mode systems, you would run this:
netapp> options nfs.per_client_stats.enable on
netapp> nfsstat -l
And on newer systems -
statistics start -object client
statistics stop
statistics show -object client -counter nfs3_ops -fields Instance, Value
If you require this information on a regular basis and for auditing purposes, there are third party products like varonis that use our fpolicy engines to record it.
Hope this helps!