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1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, and 1990. Geological Survey (U.S.). This polygon shapefile portrays the 1990 state and county boundaries of the United States, Puerto Rico, and the U.S. Virgin Islands. The map layer ... Geological Survey (U.S.).
1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, and 2005. Geological Survey (U.S.). This polygon shapefile portrays the state boundaries of the United States, and the boundaries of Puerto Rico and the U.S. Virgin Islands. The map l... Geological Survey (U.S.).