Pie
Show a small number of parts within a whole.
Use a pie when the total and its proportions matter. Keep the number of slices small; use bars when readers need precise comparisons.
A slice is a stable observation with a finite, non-negative value. The shared planner produces its sector geometry; totals and proportions are not inferred by the showcase.
Use clear labels and a compact legend. The selected slice exposes its value in a floating tooltip; presentation colours never change observation identity.