The last 3 digits (5th-7th) represent running number. It helps to distinguish one cost center from another that lies within the same activity. Refer to the above example, stream “Operation” has its activity as “Ground Operation” which can further be identified according to its business line such as “Ground Operation-CNX”. Therefore, the location of each cost center line can be differentiated using the last 3 digits of the structure that ranges from 001-999 respectively.