Year current US$ 2000 80.32628605 2001 77.95235606 2002 77.50699367 2003 91.07822701 2004 104.41970965 2005 105.08207123 2006 95.50787578 2007 88.93883826 2008 78.64821746 2009 69.26306086 2010 65.14076214 2011 72.86466598 2012 76.75169893 2013 78.48695536 2014 57.61989952 2015 36.42618375 2016 33.96101964 2017 34.62876285 2018 36.62283147 2019 37.73068246 2020 38.74578466 2021 46.78398952