Consider a corporate bond with the face value of $1,000, the coupon rate of 8% per annum, paying coupons semi-annually and the remaining term to maturity of 6 years. The current required yield-to-maturity of this bond is 6% per annum. Suppose an investor buys one bond and holds it for two years. At the end of year 2, required yield-to-maturity is expected to rise from 6% to 8% per annum. Find the investor's annual rate of return over his/her 2-year holding period.