Year current international $ 1990 8360 1991 8560 1992 9130 1993 9930 1994 9350 1995 10110 1996 10840 1997 11650 1998 8870 1999 8530 2000 9360 2001 8930 2002 9110 2003 9420 2004 10710 2005 11740 2006 13440 2007 14730 2008 15880 2009 15260 2010 17200 2011 19420 2012 20470 2013 22170 2014 23890 2015 25570 2016 26410 2017 27840 2018 27900 2019 28020 2020 28340 2021 31230 2022 37980 2023 43700