Cumulative sum in line chart for only 3 years
I have a question regarding the creation of a cumulative sum expression in a line chart.
My graph displays 10 years of data, showing actual costs , budgetted costs and expected costs. When I create a line chart, I use this expression to create cumulative sums for all cost amounts: Sum([sv_cost_amount]) THEN Sum([Value]) OVER (AllPrevious([Axis.X])).
My three cost figures are perfectly represented as three different lines running from 2017 to 2027. But my actual costs are a flat line after 2019, showing the same amount in the period 2020-2027 as the value of 2019.
Is there any possibility that I can cut off the line? As there are no actual costs yet for the 2020-2027 period, I prefer not to show the 'flat line'. I just want to show only the cumulative actual costs for the years 2017, 2018 and 2019. The other two costs figures (budgetted and expected) can stay until 2027, but my actuals should stop in 2019. I have tried different OVER aggregation expressions, but each expression didn't work out.
So if there is a solution (or it's just impossible), I'd really like to know.