Year US Dollars adjusted for inflation) 1991 1064.451 1992 1006.881 1993 975.424 1994 942.691 1995 977.512 1996 1008.722 1997 1058.342 1998 1069.348 1999 1079.115 2000 1083.496 2001 1101.581 2002 1134.539 2003 1134.157 2004 1163.565 2005 1191.212 2006 1216.088 2007 1250.826 2008 1272.063 2009 1297.696 2010 1335.56 2011 1368.717 2012 1341.238 2013 1320.71 2014 1306.103 2015 1292.738 2016 1281.45 2017 1264.382 2018 1255.482 2019 1249.457 2020 1246.2 2021 1249.526 2022 1251.375