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 7 staff members taking calls from customers. On average, one call arrives every 13 minutes. On average, each staff member spends 23 minutes with each customer.

What is the utilization rate (in percentages) of the staff members?

(Note that your answer should NOT include "%". For instance, if your answer is 20%, then you should write 20 in the blank.)