Year US Dollars adjusted for inflation) 1991 3132.321 1992 3074.636 1993 3021.084 1994 2930.731 1995 3003.882 1996 2987.042 1997 3007.726 1998 3112.592 1999 3232.54 2000 3250.358 2001 3311.518 2002 3238.865 2003 3403.875 2004 3543.958 2005 3680.938 2006 3704.748 2007 3710.218 2008 3665.687 2009 3576.557 2010 3552.592 2011 3440.872 2012 3427.787 2013 3380.186 2014 3363.192 2015 3420.191 2016 3537.273 2017 3644.316 2018 3769.212 2019 3907.941 2020 4039.518 2021 4173.623 2022 4304.727