Create webpart with Funnel by category

Hi
I have a list in SharePoint.
On behalf of that list, I want to create a funnel.



Now I want a funnel that will summ all values from my list.
So in my case the funnel should have 4 categories

Category 20 with value 205, category 50 with value 597 etc.

Is above possible?
My problem is, that I can't figure out, how to make the sum for each category, and show that in the list.