You observe a premium of $8.37 for a call option on Birdwell Enterprises common stock, which is currently selling for $47. The strike price on the call option is $48. The option has four months to maturity. The stock pays no dividends. The current risk-free interest rate is 3.0%. What is the implied volatility of the stock? (Do not round your intermediate calculations and round your final answer to the nearest whole percent.)