Your folks just called and would like some advice from you. An insurance agent just called them and offered them the opportunity to purchase an annuity for $19,999.49 that will pay them $3,500 per year for 15 years. They don't have the slightest idea what return they would be making on their investment of $19,999.49. What rate of return would they be earning? The annual rate of return your folks would be earning on their investment is _%. (Round to two decimal places.)