Here's some pretend data:
Apple 4 Apple 0 Apple 1 Banana 4 Carrot 0 Apple 0 Apple 2
I want to show the percent of each food that is exactly 0. So the ideal output:
Apple 20% Banana 0% Carrot 100%
Add a column to your data with the following formula filled down:
Then set up your pivot table to calculate the average of the new column.