Year US Dollars adjusted for inflation) 1950 5139 1951 5611 1952 5851 1953 5669 1954 6157 1955 6602 1956 6730 1957 6682 1958 6587 1959 7041 1960 7674 1961 8204 1962 8352 1963 8575 1964 9006 1965 9495 1966 9676 1967 9816 1968 9985 1969 10960 1970 11800 1971 11970 1972 12670 1973 13380 1974 14090 1975 14010 1976 13740 1977 14010 1978 14100 1979 14950 1980 15760 1981 16050 1982 16480 1983 16760 1984 17160 1985 17380 1986 17640 1987 18210 1988 19160 1989 20290 1990 19880 1991 18220 1992 17310 1993 16800 1994 17450 1995 18220 1996 18590 1997 19900 1998 21070 1999 21590 2000 22740 2001 22910 2002 23460 2003 23790 2004 24610