The files Zipcode.dat and Counties.dat are obtained from

          http://www.census.gov/geo/www/gazetteer/places2k.html



Format of Zipcode.dat as follows:

Columns 1-2: United States Postal Service State Abbreviation 
Columns 3-66: Name (e.g. 35004 5-Digit ZCTA - there are no post office names) 
Columns 67-75: Total Population (2000) 
Columns 76-84: Total Housing Units (2000) 
Columns 85-98: Land Area (square meters) - Created for statistical purposes only. 
Columns 99-112: Water Area (square meters) - Created for statistical purposes only. 
Columns 113-124: Land Area (square miles) - Created for statistical purposes only. 
Columns 125-136: Water Area (square miles) - Created for statistical purposes only. 
Columns 137-146: Latitude (decimal degrees) First character is blank or "-" denoting North or South latitude respectively 
Columns 147-157: Longitude (decimal degrees) First character is blank or "-" denoting East or West longitude respectively