Year current US$ 2011 10068116196.163107 2012 14160167981.224619 2013 15364847428.246593 2014 17976452550.096546 2015 20821719370.852337 2016 20588861390.188915 2017 22140677251.094246 2018 21746302685.711422 2019 22011340541.293987