Year constant 2011 international $ 1991 15155.6583459324 1992 14697.0124248185 1993 14629.0144597774 1994 15080.7830480698 1995 15326.7381924804 1996 15355.2609974722 1997 15900.1518665573 1998 16612.2664667884 1999 17190.3066492359 2000 17960.4720463647 2001 18693.0747343414 2002 19595.2540389586 2003 20407.7718496555 2004 21476.6692872933 2005 22463.7429843124 2006 23365.2157613087 2007 23500.2869284832 2008 23741.8849201475 2009 22209.0617657374 2010 22405.1779035861 2011 22841.2103381104 2012 22584.9144010117 2013 23121.3430648403 2014 24163.1425370978 2015 25077.2306319899 2016 25724.996828069 2017 26860.5733212723 2018 28242.944426515