Year current international $ 2000 19.48190671117217 2001 21.120307587008632 2002 21.202149470215932 2003 22.117260806911755 2004 24.388732077596707 2005 26.123439594643198 2006 26.374211086748993 2007 27.42378590939468 2008 27.189267543790248 2009 29.291713774224057 2010 28.587700963104492 2011 28.70151573235462 2012 31.865572310678726 2013 33.00844783061949 2014 34.63819068031846 2015 36.52461901312572 2016 37.95131287582845 2017 39.82943654719931 2018 41.798992005748936 2019 44.443915270665904 2020 49.660370342031385 2021 50.87335693596155