You are deciding between two mutually exclusive investment opportunities. Both require the same initial investment of $10 million. Investment A will generate $2.2 million per year (starting at the end of the first year) in perpetuity. Investment B will generate $2.1 million at the end of the first year, and its revenues will grow at 3.1% per year for every year after that. Use the incremental IRR rule to correctly choose between investments A and B when the cost of capital is 6.7%. At what cost of capital would your decision change? The incremental IRR is \%. (Round to two decimal places.)