Assume Sheryl Jenkins wants to accumulate $ 13,691.60 in two years. She currently has $ 10,400.40 to invest. What interest rate must she earn on her investment (that is, if she deposits $ 10,400.40 today) to have $ 13,691.60 exactly two years from today?(Record your answer as a percent rounded to 1 decimal place; for example, record .527945 = 52.8% as 52.8)