Darvon found a lucrative mutual fund that had an average annual interest rate of 5.6% compounded quarterly. If the interest rate average is maintained, and Darvon invests $80,000 into the fund, approximately how many years will it take for his investment to reach a million dollars? Round your answer to the nearest tenth, and enter the number only. Do not round intermediate computations as you are working, only round your final answer at the end.