C. D. Rom has just given an insurance company $33,500. In return, he will receive an annuity of $4,000 for 20 years. At what rate of return must the insurance company invest this $33,500 in order to make the annual payments? Use Appendix D for an approximate answer, but calculate your final answer using the financial calculator method. (Do not round intermediate calculations. Round your final answer to 2 decimal places.) Rate of return %