An investor purchases a 30-year U.S. government bond for $840. The bond’s coupon rate is 10 percent and, it still had twelve years remaining until maturity. If the investor holds the bond until it matures and collects the $1000 par value from the Treasury and his marginal tax rate is 25 percent (we assume that the bond is taxable), what will be his after tax (effective) yield to maturity?