Year current US$ 2000 18.38492733 2001 18.49326641 2002 15.13878894 2003 11.12837113 2004 21.90484027 2005 34.32975226 2006 42.97685234 2007 59.49875388 2008 78.96501998 2009 69.0947387 2010 76.86477594 2011 76.77762867 2012 97.5451943 2013 99.46616615 2014 95.52592252 2015 72.17015831 2016 69.79750078 2017 76.08842241 2018 78.24994392 2019 73.79609046 2020 67.05280063 2021 76.21366781