Year US Dollars adjusted for inflation) 1950 8246 1951 8590 1952 8564 1953 8956 1954 9223 1955 9515 1956 9594 1957 9701 1958 9700 1959 9968 1960 10350 1961 10500 1962 10580 1963 10910 1964 11370 1965 11590 1966 11740 1967 11990 1968 12370 1969 12550 1970 12820 1971 13130 1972 13530 1973 14510 1974 14370 1975 14260 1976 14710 1977 14820 1978 15330 1979 15750 1980 15470 1981 15310 1982 15520 1983 16060 1984 16430 1985 16970 1986 17630 1987 18400 1988 19380 1989 19780 1990 19860 1991 19530 1992 19540 1993 19960 1994 20760 1995 21270 1996 21810 1997 22470 1998 23180 1999 23800 2000 24670 2001 25130 2002 25520 2003 26040 2004 26760