Year constant 2011 international $ 1990 20166.9279938074 1991 21096.4284610415 1992 21342.8565638582 1993 20881.2060699675 1994 21026.0209145347 1995 21850.740004652 1996 22529.9200028742 1997 23422.3365254069 1998 24420.9481126354 1999 25227.3885769824 2000 25999.490687324 2001 26318.4780060543 2002 26375.9645090982 2003 26031.6495899131 2004 26439.9333354366 2005 26593.2857037278 2006 26957.6363702978 2007 27575.2364597729 2008 27590.3747959133 2009 26743.1979904258 2010 27238.4606724422 2011 26780.2149060404 2012 25805.8498346706 2013 25654.6142954091 2014 26023.6978492184 2015 26607.8328143368 2016 27205.9178026354 2017 28034.619961314 2018 28687.4842278729