You can also include the percent/ratio in your sql query and pass it as a column to the report via the result set.

Example ::

USE ADVENTUREWORKS2008R2;

Go

SELECT

personType, count(*) as Total, round( (cast(count(*) as float)/ (SELECT count(*) from person.person) ),3)*100 as PercentOfTotal

from person.person

Group by personType

This can help you get started. Make sure count(*) > 0 😀