The risk-free rate of return is 0.8% and the expected return on the market portfolio is 11%. Oklahoma Oilco has a beta of 0.72 and a standard deviation of returns of 20.5%. Oilco's marginal tax rate is 32%. Analysts expect Oilco's net income to grow by 5% per year in the foreseeable future. Flotation costs of issuing new common stock are 2.1%. 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.