Year current US$ 2007 16910321 2008 7425965 2009 4537422 2010 7200494 2011 10332315 2012 45373920 2013 73389339 2014 33923114 2015 13926421 2016 11727294 2017 14069402 2018 21177987 2019 27996627 2020 33914977 2021 22212874 2022 49457683