Year current US$ 2000 17.19779961587676 2001 17.22892249312158 2002 18.139462066301743 2003 25.395428668210165 2004 30.423104916736836 2005 34.718121625881025 2006 41.22787817101285 2007 47.80849580869086 2008 56.3517001447924 2009 53.08088217329668 2010 54.66853739510949 2011 59.8171400764046 2012 62.7015444270814 2013 69.18861357598452 2014 70.55554782579817 2015 63.39364845288592 2016 61.04014273186302 2017 58.863581053769224 2018 57.71067725431329 2019 59.35218677527115 2020 59.80583313390534 2021 65.45491330954285