Percentage memory usage per process using grafana

I am trying to capture the percentage memory usage per process in grafana using Prometheus. I am using the below query to calculate the result -

100*(sum(windows_process_working_set_private_bytes{instance=“$server”, process=~“.tcserver.”})/(windows_os_physical_memory_free_bytes{instance=~“$server”}))

But getting No data in response can someone please help me with this?