Multiply Values By Record Row - Set Analysis

[rougeherring]

I need to show a cumulative total based on multiplied values from two fields in a bar graph. 

I need to use set analysis to multiply each month's census * credits to come up with the cumulative target for each month. 

Unfortunately if I tell it to give me the months less than this month (Jan-July), sum (Census) * sum(Credits) it multiplies 1050 * 28 (29400) where as I need it to multiply and add each row independently to give me 4200. 

Month	Census	Credits	Total	Cumulative Target
January	145	4	580
February	145	4	580	1160
March	152	4	608	1768
April	152	4	608	2376
May	152	4	608	2984
June	152	4	608	3592
July	152	4	608	4200
August	152	4	608	4808
September	152	2	304	5112
October	152	4	608	5720
November	152	4	608	6328
December	152	4	608	6936

[kaushiknsolanki]

Try this.

RangeSum(Above(TOTAL Sum([Census ]*Credits), 0, RowNo(TOTAL)))