The risk-free rate of return is 1.3% and the expected return on the market portfolio is 7.3%. Oklahoma Oilco has a beta of 0.83 and a standard deviation of returns of 17.2%. Olico's marginal tax rate is 21%. Analysts expect Oilco's net income to grow by 4% per year in the foreseeable future. Flotation costs of issiling new common stock are 2.3%. Using the capital asset pricing, model, what is Oklahoma Oilco's cost of retained earnings, in \%? Drop the symbol. Eg. if your answer is 10.23%, record it as 10.23