Market value of debt is USD 1771030 and market value of equity is USD 3504295 for a company. These values are also the firm's optimum capital structure (the company doesn't use preferred shares). Current price of the firm's shares is USD 27,3. Tax rate paid by the firm is 39%. Last dividend paid by the firm was USD 3,6 and the company's earnings and dividends are expected to grow by 4,3% annually. The firm can borrow at 8,9% interest rate. What is the firm's cost of capital?