Year current US$ 1995 17000000 1996 29000000 1997 15000000 1998 31000000 1999 18000000 2000 16000000 2001 13000000 2002 14000000 2003 14000000 2004 16000000 2005 15000000 2006 16000000 2007 11000000 2008 8000000 2009 20000000 2010 7000000 2011 7000000 2012 5000000 2013 7000000 2014 8000000 2015 8000000 2016 5000000 2017 4000000 2018 13000000 2019 11000000 2020 3000000