How to create Pie chart with percentage of multiple columns

Hi,

I am using BIRT 3.7.1.

I need to create pie chart with percentage. For example,

Craft | Inspection | Repair | Maintenance | Total_Hrs
----------------------------------------------------------------------------
MECH | 40 |80 | 20 |140


So, pie chart should display,

Category:
Inspection -> 28.57%
Repair -> 57.14%
Maintenance -> 14.29%


Is it possible with BIRT pie chart? If anyone has example report, it would help a lot.

I appreciate any help!!