A company believes that its optimal capital structure consists of 55% common equity and 45% debt. Its tax rate is 25%. It must raise additional capital to fund its upcoming expansion. The firm will have $3 million of retained earnings with a cost of 12%. New common stock in an amount up to $8 million would have a cost of 15%. Furthermore, it can raise up to $4 million of debt at an interest rate of 9% and an additional $5 million of debt at 11%. The CFO estimates a proposed expansion would require an investment of $8.5 million. What is the WACC for the last dollar raised to complete the expansion? Do not round intermediate calculations. Round final answer to 2 decimals and include %,

(Hint: first step should be to calculate breakpoints)