Year current US$ 1995 67000000 1996 19000000 1997 16000000 1998 490000000 1999 403000000 2000 467000000 2001 891000000 2002 1357000000 2003 1033000000 2004 1044000000 2005 791000000 2006 1216000000 2007 1677000000 2008 1737000000 2009 2055000000 2010 2438000000 2011 2348000000 2012 2345000000 2013 3054000000 2014 3841000000 2015 4388000000 2016 4288000000 2017 4193000000 2018 5024000000