Year US Dollars adjusted for inflation) 1991 2072.512 1992 1962.956 1993 3381.438 1994 3272.973 1995 3371.708 1996 3461.283 1997 3618.223 1998 3638.377 1999 3654.782 2000 3660.066 2001 3701.282 2002 3799.59 2003 3796.667 2004 3889.401 2005 3977.977 2006 4052.566 2007 4158.17 2008 4222.626 2009 4235.228 2010 4280.333 2011 3941.518 2012 2057.25 2013 2220.712 2014 2229.729 2015 2022.256 2016 1684.45 2017 1445.423 2018 1344.281 2019 1267.786 2020 1196.63 2021 1146.763 2022 1099.743