For the most recent fiscal year, book value of long-term debt at Schlumberger was $14,481 million. The market value of this long-term debt is approximately equal to its book value. Schlumberger's share price currently is $57.44. The company has 1.000 million shares outstanding. Managers at Schlumberger estimate that the yield to maturity on any new bonds issued by the company will be 8.58%. Schlumberger's marginal tax rate would be 35%. Schlumberger's beta is 0.8. Suppose that the expected return on the market portfolio is 8% and the risk-free rate is 2%. Assume that the company will not change its capital structure. Also assume that the business risk of the projects under consideration is about the same as the business risk of Schlumberger as a whole. Whatsvould Schlumberger's after-tax WACC be given this information? Do not round at intermediate steps in your calculation. Express your answer in percent. Round to two decimal places. Do not type the % symbol