Year current US$ 2000 65.2235306 2001 69.46757616 2002 73.28533749 2003 74.97139854 2004 75.10423066 2005 74.39983502 2006 73.31708771 2007 75.64475354 2008 77.38484828 2009 73.31858453 2010 74.35776793 2011 75.20039201 2012 77.37713536 2013 82.76258176 2014 84.4330759 2015 84.15580708 2016 83.74236339 2017 82.55288073 2018 83.7438554 2019 85.82020307 2020 74.12883786 2021 87.83913783