Year current US$ 2002 60000 2004 40000 2005 110000 2006 330000 2007 560000 2010 1580000 2011 1760000 2012 3760000 2013 3150000 2014 3070000 2015 1970000 2016 1490000 2017 1640000 2018 1880000 2019 1680000 2020 2180000 2021 3850000 2022 490000