Year current international $ 2000 5.89654642107016 2001 5.40532548746289 2002 4.37293009501896 2003 5.93912807755553 2004 5.27537207132422 2005 5.86237944431344 2006 9.78079163387348 2007 13.8493400800439 2008 15.9430262448047 2009 15.8118003157132 2010 11.1305305474308 2011 10.9605815723757 2012 11.5476493169304 2013 17.4151225947233 2014 14.7417603865134 2015 16.8568937695481 2016 24.0184035472906 2017 19.2836727371283 2018 18.8563511231517 2019 19.5086335194557 2020 23.6388878787293 2021 23.6369992504462