Year current US$ 2005 293000000 2006 173000000 2007 115000000 2008 150000000 2009 115000000 2010 104000000 2011 91000000 2012 78000000 2013 76000000 2014 58000000 2015 36000000 2016 37000000 2017 30000000 2018 28000000 2019 28000000 2020 7000000