Year current US$ 1995 17000000 1996 8000000 1997 3000000 1998 15000000 1999 8000000 2000 9000000 2001 17000000 2002 15000000 2003 40000000 2004 73000000 2007 66000000 2008 133000000 2009 171000000 2010 101000000 2011 104000000 2012 135000000 2013 156000000 2014 178000000 2015 233000000 2016 206000000