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.
It is an extended zip code. In 1983, the U.S. Postal Service began using an expanded ZIP-code system called ZIP+4, often called plus-four codes or add-on codes.. This means that that every single mailable point in the country has its own 11-digit number (at least in theory).