Year US Dollars adjusted for inflation) 1991 52892.77 1992 51754.457 1993 50634.66 1994 50242.578 1995 50117.348 1996 50602.691 1997 52413.531 1998 53676.113 1999 55025.289 2000 56372.844 2001 58970.141 2002 60332.832 2003 62809.105 2004 65466.797 2005 65672.836 2006 68027.773 2007 69632.477 2008 68694.367 2009 66380.961 2010 64727.402 2011 63338.801 2012 64276.004 2013 65346.223 2014 65374.766 2015 63926.426 2016 62756.523 2017 62397.902 2018 63590.141 2019 64547.254 2020 66006.195 2021 67859.586 2022 70075.953