Year current US$ 2012 15052.3260235786 2013 16231.3915789127 2014 29650.0008553267 2015 14700.0001743436 2016 27429.999783635103 2017 34669.999033212705 2018 52372.7387189865 2019 39840.0016129017 2020 88725.3880500793 2021 135000.005364418 2022 54031.882435083404