How to find running total

[RoniDxb]

Table1
AccountNo Amount
1 ............. 500
1 ............. 500
1 .............. 500
how can we show running total in report for example if we fetch data from above table named table1 result should be look like in report as
AccountNo Amount ......Total
1 .............500 ...........500
1 .............500 ...........1000
1 .............500 ...........1500

plz help me how can i do it