We have a forecast field that has a total for each month. For the year total 13mil. We have a line chart and instead showing just the total for each month we want the total up to that month. So for January I show total January, for February we show total for January and February, and so forth to December where December will be 13mil. So the line chart will be a straight line trend for forecast. I will then add actuals to compare the two lines against.