If you only need to know what the average rate that’s in use, run the Average Rate Update report. It is used if you want to run the utility that actually updates the rates. This report won’t change anything but it will show you what the rates are now.
If you want to know the rate over a period, run the Employee Productivity History report. It will show you the average rate for the period you use to run the report.
You also might want to use the Employee Wage Rates Report; you can use the Wage Rate Type parameter to filter just for Average Rates.