Year US Dollars adjusted for inflation) 1991 21491.717 1992 16871.576 1993 14307.931 1994 13037.013 1995 13364.685 1996 13962.484 1997 14837.331 1998 15989.992 1999 15732.356 2000 17144.023 2001 18891.961 2002 19501.262 2003 20795.877 2004 22798.904 2005 24422.803 2006 26130.547 2007 28612.746 2008 29949.787 2009 27775.422 2010 29778.428 2011 30591.264 2012 31260.311 2013 32112.908 2014 32770.598 2015 33045.859 2016 32950.148 2017 34465.551 2018 36167.297 2019 37895.09 2020 39595.77 2021 41361.117 2022 43208.273