Year US Dollars adjusted for inflation) 1960 1260 1961 1274 1962 1302 1963 1264 1964 1268 1965 1236 1966 1241 1967 1258 1968 1320 1969 1334 1970 1382 1971 1395 1972 1384 1973 1315 1974 1294 1975 1268 1976 1168 1977 1173 1978 1146 1979 1207 1980 1175 1981 1057 1982 1018 1983 1013 1984 1002 1985 996.4 1986 976.7 1987 946.5 1988 944 1989 953 1990 916.4 1991 937.1 1992 879.5 1993 872.7 1994 846.5 1995 842.3 1996 845.3 1997 853.8 1998 858.2 1999 811 2000 822.9 2001 833.7 2002 727 2003 758.5 2004 750.6