Year current US$ 1998 16000000 1999 18000000 2000 19000000 2001 22000000 2002 27000000 2003 39000000 2004 45000000 2005 36000000 2006 40000000 2007 61000000 2008 64000000 2009 54000000 2010 53000000 2011 54000000 2012 57000000 2013 65000000 2014 78000000 2015 72000000 2016 65000000 2017 97000000 2018 105000000 2019 108000000 2020 51000000