Year US Dollars adjusted for inflation) 1991 23724.051 1992 17076.807 1993 10874.62 1994 12409.262 1995 12422.151 1996 17385.623 1997 16883.088 1998 17846.793 1999 15806.25 2000 17226.191 2001 16828.062 2002 17195.957 2003 17642.361 2004 18490.047 2005 19198.248 2006 19316.652 2007 19917.234 2008 20701.604 2009 20006.113 2010 20680.387 2011 21439.615 2012 20640.91 2013 21306.896 2014 21310.365 2015 21934.305 2016 22556.748 2017 22887.482 2018 23650.061 2019 24507.475 2020 25405.064 2021 26343.502 2022 27307.701