Aphid Corp. will finance its next major expansion with 60% debt, 10% preferred stock, and 30% retained earnings. Aphid's after-tax cost of debt is 4.3%, cost of preferred stock is 8.9%, and cost of retained oarnings is 11.2%. What is the corporation's weighted average cost of capital? Submit your answer as a percentage and round to two decimal places (Ex. 0.00% )