If you earn an annual interest rate of $8\mathrm{.}9$ percent, how many years will it take to double your money?

Multiple Choice

$6\mathrm{.}50$ years

$8\mathrm{.}13$ years

$7\mathrm{.}39$ years

$7\mathrm{.}11$ years

$7\mathrm{.}50$ years