function beforeDrawDataPointLabel( dph, label, icsc )
{
         currentPoint = dph.getOrthogonalValue();// or dph.getDisplayValue();
	
	index = dph.getIndex();

	
	// get previous point
	seriesArray = icsc.getChartInstance().getAxes().get(0).getAssociatedAxes().get(0).getRuntimeSeries();
	previousPoint = seriesArray[0].getDataSet().getValues()[index];
	
	// compute %
	changePercentage = ((currentPoint-previousPoint)/previousPoint)*100;
	// display if change
	if (changePercentage!=0)
	{
		label.getCaption().setValue(parseFloat(changePercentage).toFixed(2)+" %");
	}
	else
		label.getCaption().setValue("");
}