Year US Dollars adjusted for inflation) 1991 29359.182 1992 28079.844 1993 29442.68 1994 31089.049 1995 34305.414 1996 35320.758 1997 36359.152 1998 37039.789 1999 39552.23 2000 41305.223 2001 41666.25 2002 42816.059 2003 45258.004 2004 44764.645 2005 46384.281 2006 48376.395 2007 50443.336 2008 51863.098 2009 48414.293 2010 49713.004 2011 51473.855 2012 50663.898 2013 50975.801 2014 52019.625 2015 53094.977 2016 54495.574 2017 56868.656 2018 59521.508 2019 62033.387 2020 64691.145 2021 67330.969 2022 70129.578