A zero-coupon bond is a bond that is sold for less than its face value (that is, it is discounted) and has no periodic interest payments. Instead, the bond is redeemed for its face value at maturity. Thus, in this sense, interest is paid at maturity. Suppose that a zero-coupon bond sells for $9,600 and can be redeemed in 20-years for its face value of $47,000. What is the annual compound rate of return?