Year US Dollars adjusted for inflation) 1991 17507.02 1992 14604.524 1993 14593.248 1994 14875.011 1995 16554.377 1996 17675.996 1997 19705.004 1998 20611.414 1999 21230.027 2000 23956.949 2001 25767.141 2002 26974.74 2003 28408.33 2004 29851.209 2005 32074.049 2006 33554.246 2007 35701.746 2008 33809.27 2009 31898.979 2010 34197.617 2011 34753.094 2012 35445.223 2013 35560.426 2014 36311.91 2015 35951.145 2016 36409.113 2017 37912.703 2018 39300.938 2019 41029.105 2020 42939.02 2021 44947.121 2022 47025.504