Year US Dollars adjusted for inflation) 1970 1067 1971 1086 1972 1093 1973 1156 1974 1168 1975 1207 1976 1219 1977 1279 1978 1337 1979 1355 1980 1403 1981 1479 1982 1559 1983 1604 1984 1654 1985 1701 1986 1810 1987 1822 1988 1864 1989 1862 1990 1768 1991 1568 1992 1392 1993 1329 1994 1340 1995 1413 1996 1414 1997 1449 1998 1479 1999 1505 2000 1501 2001 1495 2002 1534 2003 1597