Year US Dollars adjusted for inflation) 1991 8201.229 1992 7397.246 1993 6334.51 1994 4880.475 1995 4290.971 1996 3997.422 1997 3996.386 1998 4099.947 1999 4186.854 2000 4386.616 2001 4849.21 2002 5057.945 2003 5532.503 2004 6214.376 2005 6318.235 2006 6786.354 2007 7320.608 2008 7520.329 2009 6598.565 2010 6844.74 2011 7220.171 2012 7301.877 2013 7237.99 2014 7132.765 2015 6444.348 2016 6669.753 2017 6912.888 2018 7156.758 2019 7446.509 2020 7718.786 2021 8023.593 2022 8329.46