Year US Dollars adjusted for inflation) 1970 9756 1971 10800 1972 9901 1973 15220 1974 38430 1975 43250 1976 43630 1977 44560 1978 38130 1979 42140 1980 46960 1981 43740 1982 36680 1983 31560 1984 30130 1985 27090 1986 20160 1987 20900 1988 19860 1989 22000 1990 25290 1991 24630 1992 24710 1993 22450 1994 24010 1995 25350 1996 26940 1997 28790 1998 28590 1999 29110 2000 32180 2001 32850 2002 32980 2003 35680