Based on the phone sales data and forecast attached below in the Microsoft Excel spreadsheet, what is the mean absolute deviation $($MAD$)?$ Round and enter your answer to one decimal place. Time period Month Phones sold Forecast

$1$ January $118$

$2$ February $110$

$3$ March $130114$

$4$ April $107120$

$5$ May $129118\mathrm{.}5$

$6$ June $121118$

$7$ July $147125$

$8$ August $129134$

$9$ September $138$