Hi there I have a following table

Month| Debt1 | Debt1 |TotalDebtToDate
1 | 1 | 1 | 2
2 | 1 | 2 | 5
3 | 1 | 1 | 7
4 | 2 | 1 | 10
5 | 10 | 5 | 25

Basically I have Debt1 and Debt2 given and I need to calculate TotalDebtToDate
As you see it contains sum of all debts from previous monthes(TotalDebtToDate from a row above)
+ current debt1 + current debt2

Is it possible to write such query in MS SQL 2005 for calculating TotalDebtToDate?
please help!!!
Thank you very much.