Year current US$ 2008 5550009209.99999 2009 5826615299.61656 2010 16198507551.9144 2011 22169312278.2723 2012 21960923523.1305 2013 20312610587.0831 2014 21325133340.5136 2015 18962821420.8085 2016 18989873835.3909 2017 19176779765.0717