Year current US$ 2005 477000000 2006 393000000 2007 334000000 2008 473000000 2009 361000000 2010 324000000 2011 300000000 2012 295000000 2013 326000000 2014 316000000 2015 347000000 2016 246000000 2017 171000000 2018 196500000 2019 140000000 2020 50000000