In a P system, the lead time for a box of weed$-$killer is three weeks and the review period is one week. Demand during the protection interval averages $246$ boxes, with a standard deviation of demand during the protection interval of $40$ boxes.

a$.$ What is the cycle$-$service level when the target inventory is set at $300$ boxes? Refer to the standard normal table as needed.

The cycle$-$service level is

$\%.($Enter your response rounded to two decimal places.$)$