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? $($Report a negative number if GG has the lower duration of the two.$)$