Two years ago, Gadget Geek Inc. (GG) issued a high-yield bond with a coupon rate of 15%, paying semi-annual coupons? When originally issued the bond was sold at par and had four years until maturity. Currently, GG bonds have a yield-tomaturity of 20%? By how much is the duration of GG bonds higher than that of an AAA rated zero-coupon bond with an interest rate of 7% (EAR) and 23 months until maturity?