Year US Dollars adjusted for inflation) 1960 663.6 1961 556.9 1962 596 1963 637 1964 610.6 1965 638 1966 630 1967 689.9 1968 680.7 1969 639.8 1970 805.9 1971 805.7 1972 782.2 1973 825.7 1974 794.3 1975 800.8 1976 852.5 1977 922 1978 914.1 1979 911.4 1980 894.7 1981 933.2 1982 905.6 1983 881.3 1984 857.6 1985 924.2 1986 936.7 1987 939.6 1988 1053 1989 975.7 1990 1066 1991 1101 1992 1104 1993 922.7 1994 848.2 1995 850 1996 767.7 1997 759.2 1998 780.1 1999 823.6 2000 698.8 2001 715.3 2002 760.5 2003 763.7