Year US Dollars adjusted for inflation) 1950 7091 1951 7313 1952 6736 1953 6754 1954 6950 1955 7396 1956 7353 1957 7562 1958 7949 1959 7354 1960 7859 1961 8068 1962 7968 1963 7545 1964 8031 1965 8739 1966 8569 1967 8701 1968 9005 1969 9647 1970 9740 1971 9948 1972 9946 1973 10180 1974 10590 1975 10360 1976 10110 1977 10500 1978 10090 1979 10720 1980 10810 1981 10080 1982 9493 1983 9723 1984 9829 1985 8974 1986 9533 1987 9623 1988 9228 1989 8465 1990 8231 1991 9099 1992 10050 1993 10530 1994 10970 1995 10570 1996 10910 1997 11600 1998 11930 1999 11590 2000 11330 2001 10690 2002 9561 2003 10170 2004 10940