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.
list of zip code prefixes zip codes are numbered with the first number representing a certain group of u s states the second and third numbers represent a region in that group of states or in some cases a large city the fourth and fifth numbers representing a group of delivery addresses within that region