Pie charts can't be used with any type of data. They should only be used to display part-whole relationships and contain not much more than half a dozen data values. The following screenshot shows what happens when you create a pie or doughnut chart with too much data. In this example, we loaded a doughnut chart containing the populations of almost 200 countries. It may be art, but not really a useful visualization:
Abusing a pie chart (code: Pie/pie-4-evilpie.html; see also Pie/pie-6-evilpie.html)
Even if you reduce this dataset to less than 20 values, it would still not be efficiently displayed ...
