Pie charts should be used when you want to show the different sizes each part takes in a whole.
The data show in the common statistics page don't do this.
They are different measurements that can (even this is arguable) compared between themselves. They should be presented in bar graphs.
This can't be fixed right now as apparently the Google Charts submodule of the Charts seems to have problems on bar graphs support. Probably a fix for #539572: Unable to set chart labels on X & Y Axis would fix this issue.
The current graphs are so meaningless that I believe they should be disabled. I will wait a week for any feedback on this issue.
Unless convinced otherwise at the end of this period the current charts will be disabled.
Comments
Comment #1
rsevero commentedComment #2
rsevero commentedRemoved pie charts from "Common" page and Charts module requirement.
Fixed by commit #379244.