Makarov, aged 45, wishes to accumulate a fund for retirement by depositing $1,000 at the beginning of every half-year for 15 years. Starting at age 60 he plans to make 15 annual withdrawals at the beginning of each year. Assuming that all payments are certain to be made, find the amount of each withdrawal starting at age 60, if the nominal rate of interest is 8% convertible semiannually during the first 10 years, 6% convertible semiannually for the next 5 years, and the annual effective rate if 7% thereafter.