In the Properties pane, change the Solve Order property from a blank value to 2.
By default, all the data item properties do not have this property set.
Solve Order property indicates which values will be calculated first in crosstabs and charts. The items with the lowest sort order values are calculated first; otherwise, the calculations on the detail rows are performed first, and then all the summaries.
The percentage calculation column should be calculated last, and since the summaries of the Revenue and Projected Revenue will already exist, the report server will use them to calculate the overall Year percentage.