Twelve customers visit a small bank between $9$ a$.$m$.$ and $10$:$30$ a$.$m$.$ The customers spend $8,1321,16,7,11,14,19,27,22,17$ and $10$ minutes in the bank. What is the average flow rate of customers in this bank per hour?

Multiple Choice

$9\mathrm{.}67$

$12$

$15\mathrm{.}42$

$8$