It seems like there is no such build in option.
However, there is special library for this option, it calls: “Chart PieceLabel”.
Here is their demo.
After you add their script to your project, you might want to add another option, called: “pieceLabel”, and define the properties values as you like:
pieceLabel: {
// mode 'label', 'value' or 'percentage', default is 'percentage'
mode: (!mode) ? 'value' : mode,
// precision for percentage, default is 0
precision: 0,
// font size, default is defaultFontSize
fontSize: 18,
// font color, default is '#fff'
fontColor: '#fff',
// font style, default is defaultFontStyle
fontStyle: 'bold',
// font family, default is defaultFontFamily
fontFamily: "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif"
}