Year current US$ 2007 19947348000 2008 21676178000 2009 18119039000 2010 20245774000 2011 22847603000 2012 17575520051 2013 17133941127 2014 15681722657 2015 14668165090 2016 15878515224 2017 16896040559 2018 18039318661 2019 18426664252 2020 18155662306 2021 19657869162 2022 21996652567