A savvy investor paid $5,000 for a 20-year $10,000 mortgage bond that had a bond interest rate of 10% per year, payable quarterly. Three years after he purchased the bond, market interest rates went down, so the bond increased in value. If the investor sold the bond for $13,000 three years after he bought it, what rate of return did the investor make per quarter and per year (nominal)? The rate of return per quarter is %. The rate of return per year is %