Year US Dollars adjusted for inflation) 1991 3092.859 1992 2915.597 1993 2610.205 1994 2591.034 1995 2626.681 1996 2686.126 1997 2751.946 1998 2806.153 1999 2836.825 2000 2869.669 2001 2916.211 2002 2926.761 2003 2936.835 2004 2936.985 2005 2892.462 2006 2879.305 2007 2865.055 2008 2870.299 2009 2848.45 2010 2873.153 2011 2908.925 2012 2957.095 2013 3033.942 2014 3123.24 2015 3208.362 2016 3258.527 2017 3286.583 2018 3330.628 2019 3393.858 2020 3470.501 2021 3544.367 2022 3618.998