Year US Dollars adjusted for inflation) 1991 628.57 1992 594.873 1993 571.097 1994 547.242 1995 570.082 1996 577.612 1997 605.494 1998 609.027 1999 611.503 2000 614.352 2001 621.806 2002 639.941 2003 638.557 2004 654.344 2005 668.615 2006 682.753 2007 701.101 2008 710.27 2009 724.305 2010 744.956 2011 762.214 2012 773.855 2013 784.527 2014 799.598 2015 800.2 2016 799.18 2017 808.687 2018 823.484 2019 842.228 2020 863.19 2021 884.664 2022 908.487