How to calculate data from table an pass to piechart.

I want to create pie chart like below image.i created simply pie chart in mendix.but i want to calculate value before pass to it..presently am passing to pie chart to calculate same id value and display to mentioned in below image suppose i calculated id 1 and that is 77%.may b my question is confusing if any query comment it..but please help me how to check same id and calculate it before passing.
1 answers

You could try using non-persistent objects to store the calculate values and then pass those to your widget.