This performance is the percentage time the server is busy servicing customers which is calculated by
dividing the time spent servicing customers divided by the time available. For our example, the
attendant is only idle during the time period between finish servicing customer one and the arrival of
customer two (i.e., 9.01 – 8.36 = .65 minutes). Therefore, the attendant’s utilization will be 39.35/40
or 98.4%: