Year US Dollars adjusted for inflation) 1970 2162 1971 2078 1972 2284 1973 2720 1974 3882 1975 4029 1976 2904 1977 2726 1978 2715 1979 2421 1980 1291 1981 1311 1982 1422 1983 1263 1984 1341 1985 1261 1986 1245 1987 1174 1988 1350 1989 1200 1990 1192 1991 1240 1992 1187 1993 1176 1994 1241 1995 1275 1996 1281 1997 1321 1998 1353 1999 1444 2000 1432 2001 1425 2002 1405 2003 1424