Year current US$ 2007 36172959509 2008 43492661191 2009 40395074321 2010 43607937596 2011 51148249215 2012 51279423966 2013 54346224629 2014 57101557330 2015 53795507159 2016 55536700708 2017 29833875250 2018 30114429626 2019 29872166791 2020 29244241618 2021 38184112955 2022 77973722315