Year current international $ 2000 16.8544403654296 2001 14.6715156462953 2002 15.5313301764973 2003 14.6825082968642 2004 16.1307445323434 2005 15.6322895488589 2006 16.9336286761185 2007 18.2392882447648 2008 19.7067576739286 2009 22.4532687963253 2010 20.718428281921 2011 19.0042371495908 2012 26.5119061744362 2013 27.9720766755661 2014 33.1077246896374 2015 36.8427678625751 2016 40.0380233150364 2017 45.1043793074794 2018 45.9422766595999 2019 53.0894040028463 2020 73.5835103147794 2021 61.7363580259445