One of the advantages for employees in a group health plan is the contribution most employers make toward the cost of the health coverage premium â in many cases, employers pay one-half or more of the monthly premium for an employee.
The basic format consists of five decimal numerical digits. An extended ZIP+4 code, introduced in 1983, includes the five digits of the ZIP code, a hyphen, and four additional digits that determine a more specific location within a given ZIP code. The USPS provides a free online lookup tool for ZIP codes.
Full Answer. The United States Postal Service began using two-digit area codes in 1943 in order to define postal zones in larger cities. Beginning in 1967, the ZIP code became progressively mandatory. The word ZIP comes from the acronym for Zone Improvement Plan.. The original ZIP code was composed of 5 digits.