Year US Dollars adjusted for inflation) 1991 22155.084 1992 21104.023 1993 20148.371 1994 19871.012 1995 19917.629 1996 20472.77 1997 21273.93 1998 22347.166 1999 23474.133 2000 24434.793 2001 24691.949 2002 26053.641 2003 28876.432 2004 29506.43 2005 30322.352 2006 33419.039 2007 34569.77 2008 35182.105 2009 34058.027 2010 35089 2011 34396.387 2012 34898.836 2013 35250.98 2014 34750.824 2015 34777.996 2016 32940.875 2017 33896.625 2018 35225.457 2019 36466.336 2020 37284.219 2021 37927.938 2022 38578.961