In Column E, list the names of your staff, one staff per row starting in row 2, since row one is the column name.
In Column F, beside the first staff, enter the following formula:
Make sure you replace $B$2:$B$200 with the actual range of your original data table. (You could use a named range if desired.)
Copy this formula (cell F2) into the other rows of Column F beside each staff member’s name.
The information in Column F represents the number of customers for each staff member.