Year current international $ 2000 8.00420983395161 2001 6.37271315990143 2002 8.07689005591614 2003 8.70502873069771 2004 9.21650233396172 2005 9.34148801220689 2006 10.7888248155853 2007 11.97764202392 2008 11.636550903731 2009 11.9738840814055 2010 13.6766580127206 2011 15.0478497433087 2012 16.4103557639621 2013 16.3305113279694 2014 16.8702510851157 2015 16.3797714611223 2016 21.6789144346381 2017 24.2748877040658 2018 25.4834797110273 2019 25.458310167484 2020 24.1668673132098 2021 25.9282674411757