Year current US$ 2000 50.76306208751186 2001 48.63806816862715 2002 60.6062993523959 2003 79.90896996274837 2004 100.85283192802223 2005 120.86886815838054 2006 143.38331052216836 2007 175.78369136302257 2008 211.11800787154726 2009 199.17765457756371 2010 208.3116643647807 2011 217.69079418139978 2012 227.12667943015862 2013 235.65469921968352 2014 222.69494381048958 2015 188.0689023667419 2016 186.49725348581757 2017 183.07379020545193 2018 175.14216507643056 2019 183.3340200496089 2020 200.16312796196615 2021 235.18833268966065