Year current US$ 2000 105.897595420567 2001 114.87542775377084 2002 134.44906268634497 2003 162.95249641147205 2004 203.56905606630448 2005 253.75586526265474 2006 305.24264700320316 2007 388.04251653992674 2008 488.9154381737747 2009 422.12508537759095 2010 456.20849550972565 2011 507.3279886837258 2012 532.6692729669003 2013 567.2917456772013 2014 537.3003439001543 2015 418.1720511959482 2016 407.80232504640276 2017 456.75121515017463 2018 475.8373941634858 2019 502.5745902518537 2020 554.5205041926993 2021 659.3181451650888