Year current US$ 2008 4036115 2009 4979556 2010 2641724 2011 11613670 2012 45637428 2013 16742192 2014 18069889 2015 29358261 2016 182880842 2017 36182973 2018 25098581 2019 21434893 2020 10714775 2021 9190571 2022 11237469