Year US Dollars adjusted for inflation) 1991 21857.352 1992 20690.268 1993 20290.336 1994 20301.875 1995 19562.555 1996 20935.699 1997 21499.416 1998 21702.967 1999 21823.131 2000 21617.881 2001 22414.053 2002 23376.135 2003 23602.963 2004 23283.285 2005 23660.748 2006 24070.285 2007 24739.645 2008 24536.357 2009 24955.539 2010 26523.16 2011 26962.102 2012 26937.816 2013 26790.633 2014 26792.461 2015 26186.1 2016 26320.994 2017 26613.824 2018 26831.994 2019 27132.717 2020 27313.062 2021 27587.637 2022 27943.15