Year current US$ 1995 6000000 1996 7000000 1997 7000000 1998 8000000 1999 9000000 2000 9000000 2001 9000000 2002 9000000 2003 9000000 2004 9000000 2005 10000000 2006 10000000 2007 11000000 2008 11000000 2009 13000000 2010 13000000 2011 12000000 2012 12000000 2013 13000000 2014 26000000 2015 22000000 2016 23000000 2017 19000000 2018 20000000 2019 22000000 2020 6000000