Hi I am trying to add an additional col as a percentage so i have 3 columes as Account Balance, Current and Overdue

I need an additional col as a percentage (the calculation is Overdue*100/AccountBalance) but unsure of the syntax

sum(i.unall_amount) as 'Account Balance',

sum(case when (i.kind <> 'CSH') and (due_date >= getdate()) then i.unall_amount else 0 end) as 'Current',

sum(i.unall_amount)-sum(case when (i.kind <> 'CSH') and (due_date >= getdate()) then i.unall_amount else 0 end) as 'Overdue'

Any help would be FAB