Year US Dollars adjusted for inflation) 1991 1006.985 1992 989.017 1993 978.781 1994 946.96 1995 932.843 1996 924.063 1997 928.732 1998 934.906 1999 947.496 2000 960.775 2001 982.922 2002 827.74 2003 876.366 2004 883.057 2005 884.41 2006 895.876 2007 918.81 2008 950.752 2009 880.713 2010 853.398 2011 826.606 2012 813.388 2013 810.858 2014 817.788 2015 826.657 2016 835.452 2017 848.934 2018 866.568 2019 887.918 2020 902.932 2021 917.195 2022 933.218