Five-Digit Zip Codes 1970, 1980, & 1990
ZIP Codes are administrative units established by the United States Postal Service (USPS) for the most efficient distribution of mail, and therefore generally do not respect political or census statistical area boundaries. ZIP Codes usually do not have clearly identifiable boundaries. They often serve a continually changing area; are changed periodically to meet postal requirements, and do not cover all the land area of the United States. ZIP Codes are a possible substitute for "neighborhood" if tract, BNA, and enumeration district are not available.
This data set includes socio-economic and demographic data for all ZIP codes in the US. The first data file consists of data from the 1970 Census, and has 11,957 cases and 164 variables. The second covers data from the 1980 Census, and includes 218 variables for 35,610 cases. Thid third data file covers data from the 1990 Census and includes 231 variables for 29,335 cases