Year US Dollars adjusted for inflation) 1991 36968.23 1992 38309.445 1993 37788.035 1994 38290.973 1995 39979.332 1996 40937.793 1997 41624.547 1998 41575.895 1999 42818.746 2000 43599.836 2001 43687.75 2002 43651.758 2003 43778.734 2004 44732.074 2005 45165.461 2006 45618.516 2007 46686.445 2008 46593.098 2009 46608.34 2010 48290.082 2011 49015.77 2012 49016.305 2013 49659.754 2014 49286.945 2015 49511.332 2016 49601.535 2017 50138.273 2018 50851.262 2019 51898.91 2020 53064.953 2021 54152.77 2022 55156.062