Year current US$ 2000 46.70821561201143 2001 48.295142576155946 2002 48.246672278286525 2003 46.22648482194848 2004 52.86438264283725 2005 59.83445608967186 2006 63.23116094715414 2007 76.21845752251585 2008 92.81345765971994 2009 104.76715865123737 2010 123.30757895038779 2011 137.75468704470404 2012 148.4317547752695 2013 136.97286871305974 2014 125.92900818593684 2015 128.40376649404814 2016 138.89749189975828 2017 136.6006578280838 2018 145.11486316454614 2019 135.62056777276524 2020 122.66445195227965 2021 129.05096314293948