Sets or returns the size of the center hole of a doughnut chart as a percentage of the doughnut size.

 public int SizeOfCenterHole{ get; set; }

Public Property SizeOfCenterHole() As Integer

This defaults to 50 when creating a new doughnut series.
If this is set to a value less than 10, it will be set to 10.
If this is set to a value greater than 90 it will be set to 90.

For series that are not doughnut series, setting this will have no effect and it will always return 0.