Year US Dollars adjusted for inflation) 1951 1912 1952 2015 1953 2041 1954 2100 1955 2116 1956 2138 1957 2182 1958 2154 1959 2218 1960 2339 1961 2313 1962 2328 1963 2356 1964 2469 1965 2460 1966 2426 1967 2502 1968 2537 1969 2546 1970 2661 1971 2687 1972 2972 1973 3611 1974 3875 1975 4035 1976 4321 1977 4569 1978 4704 1979 4823 1980 4939 1981 5014 1982 4924 1983 4679 1984 4690 1985 4680 1986 4684 1987 4255 1988 4595 1989 4446 1990 4453 1991 4501 1992 4506 1993 4462 1994 4511 1995 4525 1996 4532 1997 4583 1998 4492 1999 4340 2000 4314 2001 4319 2002 4297 2003 4330 2004 4516