Year current international $ 2000 32.4459541557094 2001 33.538550795913 2002 31.1728383798662 2003 33.5371745981853 2004 35.5877144828727 2005 37.0444265766952 2006 34.5282341522237 2007 29.3037226410983 2008 25.1607212651001 2009 22.3354321629369 2010 18.4557188422438 2011 15.771172398251 2012 17.1580578390378 2013 18.7790266896366 2014 18.3281187382717 2015 18.2002018562373 2016 18.0264535068087 2017 17.3004529400764 2018 17.1937401008271 2019 17.2141490925492 2020 17.2089280258794 2021 16.6729052721915