You wish to retire in 13 years, at which time you want to have accumulated enough money to receive an annual annuity of $28,000 for 18 years after retirement. During the period before retirement you can earn 9 percent annually, while after retirement you can earn 11 percent on your money. What annual contributions to the retirement fund will allow you to receive the $28,000 annuity? Use Appendix C and Appendix D for an approximate answer, but calculate your final answer using the formula and financial calculator methods. (Do not round intermediate calculations. Round your final answer to 2 decimal places.)