Sentence:  after completing the payments prescribed by paragraphs ( 2 ) and ( 3 ) of this subsection , to make payments , from time to time in ratable proportions , on account of the unpaid principal of all awards in the principal amount of more than $ 1000 , according to the proportions which the <WSD>unpaid</WSD> principal of such awards bear to the total amount in the fund available for distribution at the time such payments are made ; and after payment has been made of the principal amounts of all such awards , to make pro rata payments on account of accrued interest on such awards as bear interest . 
Meaning of the word marked with <WSD> tags:  not paid