Waiting period. Susan Norman seeks your financial advice. She wants to know how long it will take her to become a millionaire. She tells you that she has $1,698 today and wants to invest it in an aggressive stock portfolio. The historical return on this type of investment is 18% per year. How long will she have to wait if the $1,698 is the only amount she invests and she never withdraws from the market until she reaches her $1 million? (Assume no taxes on the earnings.) What if the rate of return is only 13% annually? What if the rate of return is only 9% annually? How long will Susan have to wait to become a millionaire if she invests $1,698 today at an annual rate of return of 18% ? years (Round to two decimal places.)