Changing internal radius of the semi pie chart

Situation:

You have created a semi-pie chart and want to have some white space inside for the chart to look like an arc instead. How to do that?

Solution:

You can do it by setting plotOptions.pie.innerSize to desired value. Can be a percentage or pixel value. Percentages are relative to the pie size. Pixel values are given as integers. You can use this with regular pie chart as well to create donut chart.