Year current US$ 2000 12.817126172866017 2001 12.45391728044917 2002 12.493176319847038 2003 17.00145303494724 2004 18.35834184456645 2005 21.086950320743963 2006 25.788310895722937 2007 29.959485554598267 2008 34.70424382277078 2009 31.697068265240233 2010 35.577028948551636 2011 38.74313543882195 2012 42.5622189591399 2013 46.420347255434606 2014 45.84824747978571 2015 43.43711561614223 2016 38.84377483090184 2017 39.19415662726664 2018 38.846859849655154 2019 38.92164127083434 2020 39.986663617304025 2021 43.333481835130875