You buy a share of stock, write a one-year call option with a strike price X = $18, and buy a one-year put option with a strike price X = $18. Your net initial cost to establish the entire portfolio is $17.50. 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

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