XSLT sum Income amount based on Income Type

I am new to XSLT. I have the following XML source structure:

<CURRENT_INCOME IncomeType="BASE" _MonthlyTotalAmount="25000.0000" />
<CURRENT_INCOME IncomeType="BASE" _MonthlyTotalAmount="25000.0000" />
<CURRENT_INCOME IncomeType="BONUS" _MonthlyTotalAmount="0.0000" />
<CURRENT_INCOME IncomeType="COMMISSIONS" _MonthlyTotalAmount="0.0000" />
<CURRENT_INCOME IncomeType="OVERTIME" _MonthlyTotalAmount="0.0000" />

I need to sum MonthlyTotalAmount amount based on IncomeType.

Output need look like below:

<CURRENT_INCOME IncomeType="Base" _MonthlyTotalAmount="5000.00" />
<CURRENT_INCOME IncomeType="Bonus" _MonthlyTotalAmount="0.00" />
<CURRENT_INCOME IncomeType="Commissions" _MonthlyTotalAmount="0.00" />
<CURRENT_INCOME IncomeType="Overtime" _MonthlyTotalAmount="0.00" />

Any small help will be much appreciated.