SharePoint Dashboard

I need to create a dashboard in SharePoint that shows a sum of values per category.

Example:

Display this: Category 1 – 5 Category 2 – 3 Category 1 – 7 Category 3 – 4 Category 2 – 5

as this … Category 1 – 12 Category 2 – 8 Category 3 – 4

I tried google charts, but I was unable to figure out how to summarize data. Any suggestions?