Year current US$ 2000 47.50006104 2001 45.25306702 2002 51.05594635 2003 63.81992722 2004 70.50469971 2005 67.78135681 2006 65.70906067 2007 69.87508392 2008 73.73594666 2009 69.42589569 2010 69.0898819 2011 80.95452881 2012 76.77297974 2013 81.4433136 2014 84.27106476 2015 60.86703491 2016 63.14864731 2017 74.52148438 2018 74.43584442 2019 77.80075073 2020 88.67053223 2021 99.03723907