when did the united states start using zip codes
ZIP Code ZIP Codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP is an acronym for Zone Improvement Plan;[1] it was chosen to suggest that the mail travels more efficiently and quickly (zipping along) when senders use the code in the postal address. The basic format consists of five digits. An extended 'ZIP+4' code was introduced in 1983 which includes the five digits of the ZIP Code, followed by a hyphen and four additional digits that reference a more specific location.
Ten-code The codes, developed in 1937 and expanded in 1974 by the Association of Public-Safety Communications Officials-International (APCO), allow brevity and standardization of message traffic. They have historically been widely used by law enforcement officers in North America, but, due to the lack of standardization, in 2006 the U.S. federal government recommended they be discontinued in favor of everyday language.[1]