You buy a share of stock, write a one-year call option with a strike price X = $13, and buy a one-year put option with a strike price X = $13. Your net initial cost to establish the entire portfolio is $12.50. What must be the risk-free interest rate from now until the options maturity date? The stock pays no dividends. (Do not round intermediate calculations. Enter your answer as a percentage rounded to two decimal places.) Risk-free rate