Year current US$ 1995 21000000 1996 26000000 1997 18000000 1998 21000000 1999 36000000 2000 40000000 2001 42000000 2002 44000000 2003 46000000 2004 43000000 2005 42000000 2006 41000000 2007 43000000 2008 41000000 2009 41000000 2010 36000000 2011 34000000 2012 37000000 2013 40000000 2014 49000000 2015 47000000 2016 53000000 2017 51000000 2018 48000000 2019 43400001.5258789 2020 20549999.237060502