James McCulloch purchased a 20-year U.S. Treasury bond four years ago for $2,500. The bond paid 3.20 percent annual interest. Four years later he sold the bond for $2,520. What is the annual interest amount for the bond? (Round your answer to 2 decimal places.) What is the total interest Mr. McCulloch earned during the four-year period? What is the total return for Mr. McCulloch's bond investment