Year current US$ 2000 51.55858793 2001 65.24680588 2002 70.25167613 2003 72.57032129 2004 78.64595807 2005 88.50482729 2006 95.42688966 2007 103.02828195 2008 112.08709445 2009 102.3845701 2010 111.30715355 2011 120.74814925 2012 125.44972762 2013 117.01709156 2014 128.35404733 2015 140.9609294 2016 149.3101358 2017 167.25934103 2018 165.58419859 2019 169.10078218 2020 175.5978499 2021 217.88052677