You estimate that a passive portfolio invested to mimic the S&P 500 stock index yields an expected rate of return of 10% with a standard deviation of 19%. Assume you manage a risky portfolio with an expected rate of return of 12% and a standard deviation of 24%. The T-bill rate is 5%. How much could you charge as a portfolio manager before your client would be better off in the S&P 500 portfolio? Convert your answer to a percentage and round to one decimal place