Year US Dollars adjusted for inflation) 1991 26080.715 1992 25996.752 1993 26022.332 1994 26468.982 1995 27913.863 1996 29069.414 1997 29116.188 1998 29420.447 1999 30540.221 2000 32099.877 2001 32871.773 2002 33051.301 2003 34507.66 2004 36511.363 2005 38312.82 2006 40511.629 2007 41934.984 2008 42571.469 2009 41130.215 2010 42347.938 2011 42961.906 2012 42431.93 2013 41777.863 2014 42550.793 2015 43937.289 2016 44118.688 2017 45766.371 2018 47111.25 2019 48781.559 2020 50116.195 2021 51336.027 2022 52569.598