In 1976, Manhattan Island was assessed at $18,000,000,000. According to legend, it was purchased by Peter Minuit for $24 in 1626. Supposed instead that he had deposited his $24 in a savings account with a "guaranteed forever" interest rate, compounded continuously. What interest rate would he have had to lock in so that he would have $18,000,000,000 in 1976?

The interest rate would be __%.