Year current US$ 2000 3686000000 2001 4367000000 2002 4350000000 2003 4385000000 2004 5783000000 2005 8277000000 2006 8738000000 2007 10690000000 2008 12083000000 2012 14107000000 2013 13884000000 2014 17492000000 2015 17686000000 2016 19184000000 2017 21856000000 2018 25790000000 2019 28595000000 2020 15777000000