Year current US$ 2000 59.30676366678446 2001 58.89712342929218 2002 57.26398282996149 2003 64.06089563784758 2004 73.53413561457457 2005 85.8621067849039 2006 98.32137922677065 2007 117.14032626622185 2008 138.50672155278892 2009 145.21312370124562 2010 167.55102673555373 2011 194.0240620200044 2012 205.92148593382322 2013 221.10377077736285 2014 228.47194966236268 2015 223.21271276209023 2016 222.13144115241133 2017 238.8039689414732 2018 250.50148482554616 2019 257.0576554612094 2020 260.7397803269507 2021 294.47439968413585