A firm's total assets are $1646 mln. The firm funds the assets with $218 mln of debt, $69 mln. of preferred stock, and the remainder with common equity. What is the firm's WACC if its pre- tax cost of debt is 5.7%, cost of preferred stock is 7.9%, cost of common equity is 13.1%, and the tax rate is 17% ? Express your answer in %, to the nearest 0.01% ; drop the % symbol