Year current US$ 2012 42995227.84248247 2013 41768999.51693162 2014 34386981.06066839 2015 33462939.904819377 2016 40400521.71517916 2017 27954495.435514823 2018 30785877.05394833 2019 23164357.42138887 2020 24907692.307692308 2021 26787151.080027234