Year current US$ 1995 5000000 1996 5000000 1997 6000000 1998 6000000 1999 7000000 2000 9000000 2001 8000000 2002 8000000 2003 8000000 2004 10000000 2005 11000000 2006 14000000 2007 12000000 2008 15000000 2009 11000000 2010 13000000 2011 14000000 2012 15000000 2013 16000000 2014 39000000 2015 37000000 2016 37000000 2017 42000000 2018 41000000 2019 42000000 2020 13000000