Year current international $ 2003 17.7597253105302 2004 23.4470466504303 2005 29.1642147884842 2006 19.8393347767003 2007 15.7861233015516 2008 13.2903980735496 2009 11.7876690389102 2010 14.9552122339796 2011 14.6465851900932 2012 15.5004124248356 2013 14.6630758224869 2014 23.4611556512723 2015 25.0118482211866 2016 24.0963315995165 2017 24.6515471245008 2018 20.3420323579004 2019 20.4349150784143 2020 24.9266163519289 2021 16.0381659683204