Year current US$ 1995 18000000 1996 26000000 1997 28000000 1998 24000000 1999 38000000 2000 25000000 2001 25000000 2002 33000000 2003 54000000 2004 62000000 2005 29000000 2006 26000000 2007 29000000 2008 31000000 2009 33000000 2010 31000000 2011 31000000 2012 31000000 2013 29000000 2014 32000000 2015 35000000 2016 26000000 2017 31000000 2018 49000000 2019 55000000 2020 30000000