Year current US$ 2007 20000000 2008 26000000 2009 49000000 2010 56000000 2011 54000000 2012 79000000 2013 78000000 2014 73000000 2015 73000000 2016 69000000 2017 77000000 2018 68000000 2019 70000000 2020 25000000