Find a Doctor is a small startup that helps people find a physician that best meets their needs $($location$,$ insurance accepted, etc$).$ During a "slow" time for them, they have $8$ staff members taking calls from customers. On average, one call arrives every $5$ minutes. On average, each staff member spends $18$ minutes with each customer. $($Round your answer to $1$ decimal place.$)$ What is the probability that one of their staff members is busy?