Year US Dollars adjusted for inflation) 1960 791.08535 1961 888.01585 1962 868.93504 1963 827.27338 1964 1025.95706 1965 1157.16553 1966 1126.33856 1967 1132.81205 1968 1212.26355 1969 1191.97261 1970 1296.36165 1971 1282.25462 1972 1236.29234 1973 1145.80653 1974 1248.41135 1975 1150.53495 1976 1213.35833 1977 1156.83529 1978 1118.43301 1979 1138.83473 1980 1143.86 1981 1149.71163 1982 1090.89903 1983 1099.59489 1984 1034.2349 1985 1035.63975 1986 1064.72662 1987 1055.37224 1988 1044.48609 1989 1065.01874 1990 1018.27052 1991 1009.10877 1992 1001.02076 1993 1031.7071 1994 972.88075 1995 1038.26412 1996 1066.51937 1997 992.59553 1998 989.10332 1999 1033.13926 2000 998.10697 2001 988.47025 2002 966.47293 2003 995.19465 2004 1022.75037 2005 1083.19527 2006 1251.63016 2007 1251.15438 2008 1229.45439 2009 1182.37837 2010 1203.38366 2011 1223.3446 2012 1256.20197 2013 1293.55549 2014 1326.15865 2015 1306.64958 2016 1296.0074 2017 1305.20504