Year current US$ 2002 21000000 2003 30000000 2004 42000000 2005 50000000 2006 62000000 2007 87000000 2008 103000000 2009 93000000 2010 88000000 2011 99000000 2012 96000000 2013 76000000 2014 78000000 2015 54000000 2016 51000000 2017 47000000 2018 59000000 2019 45000000 2020 38000000