Donut Chart

A Doughnut Chart or Doughnut Graph is a variant of the pie chart, with a blank center allowing for additional information about the data as a whole to be included.
Each point is specified by an arc that length is proportional to the circumference as the data value to the total sum of all values.

Very often Circular Gauges are used to get more beautiful visualization instead of Pie charts.
(take a look at Circular_Gauges/Solid_Gauge sample)