Year US Dollars adjusted for inflation) 1991 17631.861 1992 18659.375 1993 19108.404 1994 20015.455 1995 21548.092 1996 23051.922 1997 24130.65 1998 24610.234 1999 24987.125 2000 26253.646 2001 26635.273 2002 27089.348 2003 27412.891 2004 28199.783 2005 29301.504 2006 30155.336 2007 30143.326 2008 30470.242 2009 30342.166 2010 29808.996 2011 30237.098 2012 31226.459 2013 31861.898 2014 32108.191 2015 32349.457 2016 32623.188 2017 32883.258 2018 33809.613 2019 34508.938 2020 35152.348 2021 35806.422 2022 36479.98