A bond investor is considering two 10 year maturity bonds both rated AAA: the municipal bond is yielding 1.35% and the corporate bond is yielding 2.10%. At what marginal tax rate would the bond investor be indifferent between the two bonds? Enter your answer rounded off to two decimal points. Do not enter % in the answer box. For example, if your answer is 0.12345 or 12.345% then enter as 12.35 in the answer box.