Year current US$ 1995 36764000000 1996 37058000000 1997 33009000000 1998 28806000000 1999 32772000000 2000 31884000000 2001 26531000000 2002 26656000000 2003 28958000000 2004 38252000000 2005 37565000000 2006 26876000000 2007 26511000000 2008 27901000000 2009 25199000000 2010 27950000000 2011 27262000000 2012 27906000000 2013 21861000000 2014 19314000000 2015 15974000000 2016 18562000000 2017 18188000000 2018 20198000000 2019 21277000000 2020 5448000000