Year current US$ 2003 0.4540005128837686 2004 1.0488553823767117 2005 0.8358769143385307 2006 1.1407719843454005 2007 1.682510218939948 2008 1.0613240720659958 2009 1.518496419279919 2010 0.9896903761317157 2011 1.1065164908478577 2012 1.1238835367677722 2013 1.0969608734602714 2014 1.8861106567286583 2015 1.307351826940488 2016 1.447799656187973 2017 1.087780275149716 2018 0.9503614503535713 2019 1.5850815079495755 2020 2.442001132509526 2021 3.432343419074792