Year current US$ 1998 4099999.9999999995 1999 9200000 2000 9900000 2001 6200000 2002 6900000 2003 7400000 2004 7700000 2005 7300000 2006 6700000 2007 5000000 2008 7700000 2009 8300000.000000001 2010 11100000 2011 15900000 2012 15000000 2013 30900000 2014 56100000 2015 62500000 2016 69100000 2017 65900000.00000001 2018 71900000