Year current US$ 2009 4864092 2010 4619872 2011 3285632 2012 4737341 2013 53489209 2014 72921911 2015 11881005 2016 4109929 2017 17744305 2018 5845178 2019 1838136 2020 8771623 2021 12797212 2022 5916151