Year constant 2010 US$ 2006 582.442643895432 2007 604.776697171116 2008 573.433723690502 2009 560.145537714329 2010 537.741566397523 2011 547.05166343627 2012 577.227584856068 2013 612.714241088849 2014 585.223757539793 2015 596.359885532896 2016 607.993897176112 2017 608.381284050033 2018 640.568705289919