Year current US$ 2003 12.09246693 2004 35.83777257 2005 35.16683309 2006 34.55283435 2007 63.16136878 2008 106.88071039 2009 106.61477217 2010 105.48747738 2011 119.39199235 2012 64.95168051 2013 75.80662798 2014 66.24980554 2015 34.33906337 2016 110.19421555 2017 81.41858065 2018 113.42293615 2019 118.28120441 2020 110.55043054 2021 122.82300216