Year current US$ 2000 28.10793712541565 2001 28.60408854063606 2002 30.911887147453808 2003 34.04558639131408 2004 37.47720588669854 2005 42.06992743097114 2006 46.39290592528578 2007 52.50551745338442 2008 63.97110441879864 2009 70.73663244842552 2010 80.16217178120868 2011 97.43797709674209 2012 108.3911421420066 2013 118.52387355658126 2014 124.01675282465166 2015 127.45104085866241 2016 134.8182711887192 2017 151.84945539566806 2018 172.77192491635947 2019 185.91070942001218 2020 203.40312647110312 2021 234.98909298075134