Year current US$ 2007 58000000 2008 80000000 2009 76000000 2010 72000000 2011 70000000 2012 67000000 2013 81000000 2014 79000000 2015 69000000 2016 91000000 2017 91000000 2018 73000000 2019 72000000 2020 38000000