An investor purchases a 30-year U.S. government bond for $840. The bonds 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?