If you have been entering analysis after receiving fruit this information will be available for you in the Crush/Extraction report located under Winery Reports -> Vintage/Harvest.
Set the option to run the report by Fruit origin and the correct Vintage. Then choose to group by Grower and Varietal. Click Generate to run the report.
The output will show the Average analysis information as well as the total tonnes received and volume extracted from each unique Grower / Varietal combination.