Year current US$ 1995 31000000 1996 30000000 1997 29000000 1998 34000000 1999 36000000 2000 26000000 2001 12000000 2002 14000000 2003 14000000 2004 35000000 2005 51000000 2006 14000000 2007 6000000 2008 6000000 2009 6000000 2010 8000000 2011 8000000 2012 8000000 2013 8000000 2014 8000000 2015 11000000 2016 9000000 2017 15000000 2018 17000000 2019 11000000 2020 4000000