Year US Dollars adjusted for inflation) 1991 45084.941 1992 44257.574 1993 44403.898 1994 45397.727 1995 46598.008 1996 47770.492 1997 48907.09 1998 50202.434 1999 51609.402 2000 53209.938 2001 54813.523 2002 55852.879 2003 57024.059 2004 58406.789 2005 59614.074 2006 60664.309 2007 61937.773 2008 61941.148 2009 59218.785 2010 58985.969 2011 59846.266 2012 60201.293 2013 60873.988 2014 62183.918 2015 63715.141 2016 64701.992 2017 65879.164 2018 66765.734 2019 67842.586 2020 69074.93 2021 70427.742 2022 71838.344