How To sum continues accumulating amount in column

[Step]

I would like it to be like this in pivot table;

Year,Month,amount

Year	jan	feb	march	april	may	jun	july	aug	etc
2013	1	2	3	4	5	6	7	8	9
2014	10	11	12	13	14	15	16	17	18
2015	19	20	21	22	23	24	25	26	27
2016	28	29	30	31	32	33	34	35	36
2017	37	38	39	40	41	42	43	44	45

instead i got this:

I used this expression RangeSum(Before(Sum(Amount), 0, ColumnNo()))

year	jan	feb	march	april	may	jun	july	aug	etc
2013	1	2	3	4	5	6	7	8	9
2014	1	2	3	4	5	6	7	8	9
2015	1	2	3	4	5	6	7	8	9
2016	1	2	3	4	5	6	7	8	9

[Anil_Babu_Samineni]

How is your input data set?

[Step]

assume all are 1, i just add them up per column

[Step]

Year	Jan	feb	march	apr	may	jun	july	aug	etc
2013	1	1	1	1	1	1	1	1	1
2014	1	1	1	1	1	1	1	1	1
2015	1	1	1	1	1	1	1	1	1
2016	1	1	1	1	1	1	1	1	1

lets assume all are 1