Year US Dollars adjusted for inflation) 1991 9973.886 1992 10424.047 1993 10745.442 1994 10980.85 1995 11241.137 1996 11652.196 1997 12063.238 1998 12526.611 1999 12588.293 2000 13497.666 2001 13563.83 2002 13916.965 2003 14555.583 2004 15590.586 2005 15724.501 2006 16884.1 2007 17725.02 2008 18196.967 2009 18647.6 2010 19114.406 2011 19899.465 2012 20369.221 2013 20663.607 2014 21018.756 2015 21439.316 2016 22161.398 2017 23017.213 2018 23958.438 2019 24909.938 2020 25828.834 2021 26753.377 2022 27684.625