Year US Dollars adjusted for inflation) 1965 1113.19282 1966 1128.57679 1967 1106.69902 1968 1195.52309 1969 1224.96614 1970 1254.2347 1971 1356.58082 1972 1562.58033 1973 1518.51686 1974 1605.08224 1975 1681.6917 1976 1773.57929 1977 1792.77309 1978 1864.14439 1979 1938.45424 1980 2028.98009 1981 2083.01008 1982 2014.57033 1983 2049.11915 1984 2106.86267 1985 2166.91358 1986 2082.13092 1987 2168.95351 1988 2121.10365 1989 2110.04297 1990 2227.47056 1991 2263.60845 1992 2387.671 1993 2389.50095 1994 2418.1837 1995 2432.31251 1996 2566.12859 1997 2668.81055 1998 2762.55429 1999 2897.98369 2000 3004.61077 2001 3091.10277 2002 3107.02064 2003 3228.46383 2004 3403.10523 2005 3492.16594 2006 3641.5434 2007 3847.40697 2008 3968.35256 2009 4044.62969 2010 4140.15177 2011 4014.91679 2012 4127.40109 2013 4196.78421 2014 4271.32685 2015 4270.87405 2016 4269.13977 2017 4303.96361