Highcharts donut chart customization

Question

I have a license for highcharts and I would like to create a char like the one bellow:

Answer 1

 function(chart4) {
chart4.renderer.text('Reduced by 
10 Years', (chart4.chartWidth/2)-38, (chart4.chartHeight/2)-5)
             .css({

                color: '#4b4b4b',
                fontWeight: 'bold',
                fontSize: '12px'

            })
            .add();
}