Year US Dollars adjusted for inflation) 1960 1373 1961 1496 1962 1404 1963 1326 1964 1434 1965 1374 1966 1641 1967 1962 1968 2056 1969 1959 1970 2098 1971 2091 1972 2156 1973 1997 1974 2080 1975 1849 1976 1889 1977 1899 1978 1899 1979 1922 1980 1930 1981 2055 1982 2108 1983 2372 1984 2493 1985 2720 1986 2765 1987 2751 1988 2933 1989 2966 1990 2861 1991 2944 1992 2966 1993 3174 1994 3111 1995 3490 1996 3523 1997 3890 1998 4176 1999 4487 2000 4983 2001 4810 2002 4939 2003 5120