Every post office branch employs a number of postal service clerks for the day-to-day operation of the office and the management of various tasks throughout the office. Most of these tasks are customer-facing responsibilities that require a positive attitude throughout the day in order to meet all of their customers' needs.
In 2011, almost half a trillion pieces of mail—letters, postcards, and packages—were shipped worldwide using national mail service agencies. The United States Postal Service handled almost 40 percent of this worldwide traffic, with 168 billion pieces of domestic and international mail passing through 31,509 postal branches. Within any postal service branch in the world, the clerks hired are responsible for the processing of this large quantity of mail, even with competition from other private shipping services.