The risk-free rate of return is 2.9% and the expected return on the market portfolio is 10.2%. Oklahoma Oilco has a beta of 1.94 and a standard deviation of returns of 22.8%. Oilco's marginal tax rate is 26%. Analysts expect Oilco's net income to grow by 3% per year in the foreseeable future. Floatation costs of issuing new common stock are 3.1%. Using the capital asset pricing model, what is Oklahoma Oilco's cost of retained earnings, in %? Drop the % symbol. E.g., if your answer is 10.23%, record it as 10.23.