Year US Dollars adjusted for inflation) 1991 1228.239 1992 994.855 1993 1016.518 1994 1002.69 1995 921.946 1996 937.84 1997 877.571 1998 884.123 1999 848.764 2000 881.732 2001 788.746 2002 954.57 2003 994.31 2004 986.765 2005 1000.358 2006 1035.643 2007 1103.095 2008 1147.822 2009 1186.182 2010 1233.719 2011 1278.768 2012 1456.782 2013 1736.444 2014 1788.885 2015 1375.419 2016 1426.396 2017 1467.461 2018 1525.207 2019 1591.994 2020 1681.005 2021 1774.393 2022 1870.141