Percent Line Chart

Hi,

I need to create a line chart of percentage.
On my table there is four columns: Month, Territory , Total Contacts, Total Sales

My objective is to make a line chart by month (X axis) with percentage of sucess on contacts (Y axis is [Total Sales] / [Total Contacts] ).

This same chart have to show a Territory Filter, and the user will be able to view the perfomance by territory.

How Can I do this, without create one view for each territory ?

regards,

Delio Tomaz