Olsen Outfitters Inc. believes that its optimal capital structure consists of 50% common equity and 50% debt, and its tax rate is 40%. Olsen must raise additional capital to fund its upcoming expansion. The firm will have $1 million of retained earnings with a cost of rs = 13%. New common stock in an amount up to $7 million would have a cost of re = 17%. Furthermore, Olsen can raise up to $3 million of debt at an interest rate of rd = 9% and an additional $4 million of debt at rd = 11%. The CFO estimates that a proposed expansion would require an investment of $3.1 million. What is the WACC for the last dollar raised to complete the expansion? Round your answer to two decimal places.