This example produces a donut chart that is similar to the pie chart in Specifying the Sum Statistic for a Pie Chart in that each slice represents total sales for a site and each slice is a different ...

The concentric rings of the subgrouped pie or donut chart make it easy to compare slice values between subgroups. In addition, you can use global statements to modify patterns and legends, as well as ...

The Graph Makeover Contest makes it clear that there are multiple ways to plot a data set with no one way being best. This post shows alternatives to a pair of donut charts.