You were hired as a consultant to Quigley Company, whose target capital structure is $35\%$ debt, $10\%$ preferred, and $55\%$ common equity. The interest rate on new debt is $5\mathrm{.}76\%,$ the yield on the preferred is $8\mathrm{.}72\%,$ the cost of retained earnings is $18\mathrm{.}78\%,$ and the tax rate is $20\%.$ The firm will not be issuing any new stock. What is Quigley's WACC?