Year current international $ 2000 26.2479297598411 2001 22.8638566588499 2002 24.9475918818757 2003 20.0282407750321 2004 10.6196047389797 2005 12.0582404654513 2006 13.725277308215 2007 14.8260955381945 2008 15.9681745514329 2009 16.4673135960836 2010 16.7439289807514 2011 17.2190859025218 2012 16.8785816190631 2013 16.037433594729 2014 15.3472546566971 2015 14.2302297014933 2016 18.6982258758574 2017 17.2394505952637 2018 15.461469040576 2019 13.8626897415851 2020 13.9682048526483 2021 14.8417066037729