asp.net - How to set Chart control width into percentage

In asp.net chart control, how do we set chart width into percentage, below scenario is chart width needs to be set with the panel width. As the chart takes only pixel. Help on this.

code behind:
protected void Page_Load(object sender, EventArgs e)
{

Chart2.Series[0].Points.AddXY(1, 1);
Chart2.Series[0].Points.AddXY(1, 2);
Chart2.Series[0].Points.AddXY(2, 1);
Chart2.Series[0].Points.AddXY(2, 2);
Chart2.Series[0].Points.AddXY(3, 1);
Chart2.Series[0].Points.AddXY(3, 2);


Chart3.Series[0].Points.AddXY(1, 10);
Chart3.Series[0].Points.AddXY(1, 20);
Chart3.Series[0].Points.AddXY(2, 10);
Chart3.Series[0].Points.AddXY(2, 20);
Chart3.Series[0].Points.AddXY(3, 10);
Chart3.Series[0].Points.AddXY(3, 20); 

}