Year current US$ 1995 35000000 1996 29000000 1997 16000000 1998 20000000 1999 26000000 2000 12000000 2001 17000000 2002 20000000 2003 21000000 2004 29000000 2005 27000000 2006 34000000 2007 72000000 2008 64000000 2009 53000000 2010 57000000 2011 53000000 2012 43000000 2013 39000000 2014 54000000 2015 62000000 2016 64000000 2017 50000000 2018 31000000 2019 94000000