Year current US$ 2000 109.87869837 2001 84.06951261 2002 101.72137312 2003 72.80430554 2004 94.46599789 2005 93.82108864 2006 88.73376242 2007 126.24470727 2008 149.22807097 2009 131.23795684 2010 147.31263366 2011 162.87752377 2012 149.28616553 2013 152.88172365 2014 152.80240392 2015 180.70217607 2016 182.10039043 2017 214.3664359 2018 217.55883592 2019 223.84369714 2020 221.48585277 2021 265.16850808