Year US Dollars adjusted for inflation) 1991 6903.769 1992 8769.745 1993 10965.54 1994 11067.351 1995 10927.91 1996 11514.932 1997 13508.977 1998 17602.564 1999 20098.688 2000 19902.076 2001 19812.869 2002 17940.977 2003 11552.811 2004 17352.65 2005 17077.402 2006 17668.021 2007 16928.188 2008 17302.248 2009 17395.436 2010 17983.58 2011 18729.969 2012 20732.854 2013 21344.596 2014 20627.504 2015 20803.018 2016 22480.764 2017 21749.252 2018 21613.469 2019 21592.064 2020 21596.025 2021 21960.619 2022 22385.516