Year current US$ 2007 665000000 2008 667000000 2009 619000000 2010 681000000 2011 729000000 2012 854000000 2013 871000000 2014 922000000 2015 913000000 2016 871000000 2017 646000000 2018 468000000 2019 708000000 2020 243000000