SSRS Ratio is matrix

SSRS Ratio is matrix

I created the following Matrix in SSRS:
[Account] Total
Deposits [Sum(Deposit)] [Sum(Deposit)]
Withdrawals [Sum(Withdrawals)] [Sum(Withdrawals)]
Withdrawal Ratio ?????????? =Sum(Fields!Withdrawals.Value,
"DataSet1")/Sum(Fields!Deposit.Value, "DataSet1")
The [Account] column is a group. Currently we have 2 different types of
Accounts. I'm trying to calculate the withdrawal ratio
(Withdrawals/Deposits). It works for the total. But I can't get it to work
for the individual groups. It displays the ratio for the combined
accounts.
Any thoughts? Thanks!