Thirteen years ago, Mr. Lawton rolled a $18,000 retiring allowance into an RRSP that subsequently earned 10.1% compounded semiannually. Four years ago he transferred the funds to an RRIF. Since then, he has been withdrawing $1100 at the end of each quarter. If the RRIF earns 8.1% compounded quarterly, how much longer can the withdrawals continue? (Do not round intermediate calculations and round up the number of payments, n, to the next whole number.)