Year current international $ 2000 31.561293379897137 2001 32.36910878190471 2002 35.559664866903034 2003 37.22350792031776 2004 38.573335428113246 2005 40.10669997644636 2006 44.16648694919249 2007 46.673424776871606 2008 48.07308653432957 2009 48.867056002359085 2010 49.29642672732434 2011 50.357831176685714 2012 51.31557408803195 2013 57.17844037002334 2014 58.9891596896996 2015 61.75139406891077 2016 64.79442855845551 2017 62.85672648567388 2018 60.6740191898659 2019 63.73706210138229 2020 62.05723499885159 2021 65.32380630731085