Year US Dollars adjusted for inflation) 1960 1299.94925 1961 1276.28521 1962 1301.35336 1963 1383.48257 1964 1421.37894 1965 1459.25359 1966 1367.48827 1967 1127.44303 1968 1089.14462 1969 1322.7572 1970 1616.18743 1971 1803.95614 1972 1821.18208 1973 1873.16322 1974 2029.44666 1975 1871.75787 1976 1983.03689 1977 2040.26382 1978 1865.00944 1979 1932.56837 1980 1957.09878 1981 1654.63342 1982 1595.1456 1983 1476.66534 1984 1410.67882 1985 1489.42397 1986 1324.11519 1987 1151.12561 1988 1205.80462 1989 1250.68277 1990 1374.43676 1991 1331.612 1992 1304.09028 1993 1298.44095 1994 1277.99293 1995 1242.73805 1996 1272.72925 1997 1276.24082 1998 1278.65132 1999 1253.04789 2000 1287.05926 2001 1310.50597 2002 1326.24297 2003 1426.90331 2004 1860.06238 2005 1875.02964 2006 1976.70847 2007 2056.83859 2008 2128.66663 2009 2216.49939 2010 2327.32067 2011 2376.63877 2012 2412.86078 2013 2475.94806 2014 2563.09212 2015 2562.52222 2016 2455.91856 2017 2412.41