Year US Dollars adjusted for inflation) 1991 34035.172 1992 35488.223 1993 36691.793 1994 38672.305 1995 40113.902 1996 41494.492 1997 42959.785 1998 44676.156 1999 45941.992 2000 47990.352 2001 47702.508 2002 48931.195 2003 50266.188 2004 51427.078 2005 52492.27 2006 52542.48 2007 53058.945 2008 53903.652 2009 52439.422 2010 53065.277 2011 52222.535 2012 52393.641 2013 53203.008 2014 55920.199 2015 58914.449 2016 60729.41 2017 64102.16 2018 67326.227 2019 69963.727 2020 71982.32 2021 73362.312 2022 74834.992