Year US Dollars adjusted for inflation) 1991 21564.277 1992 21844.27 1993 22587.678 1994 23664.508 1995 24538.303 1996 25382.424 1997 24225.676 1998 24707.746 1999 23873.779 2000 23217.637 2001 23023.258 2002 22459.787 2003 21802.322 2004 21899.271 2005 21588.279 2006 21304.908 2007 22906.938 2008 24336.91 2009 25891.537 2010 26839.92 2011 25777.939 2012 24482.123 2013 22926.824 2014 21917.684 2015 21157.504 2016 20746.152 2017 20992.623 2018 21425.941 2019 21953.932 2020 22619.238 2021 23793.064 2022 25007.838