31. A firm plans to issue a $1000 par value, 20-year non-callable bond with a 7% coupon rate paid semiannually. The firm forecasts its proceeds after discounting the bonds and floatation costs will be 98.795. The company's marginal tax rate is curretly 35%, but Congress is considering a change in the corporate tax rate to 15%. By how much would the effective cost of the debt change if the new tax rate is adopted?