Year constant 2015 US$ 2006 18733346.675632134 2007 19167292.124603085 2008 15912607.975840071 2009 20155143.00693378 2010 17872638.451716613 2011 23595364.02113171 2012 34640637.60706306 2013 44690970.91811819 2014 44195179.8473356 2015 72808900.97589193 2016 61266636.157590136 2017 53201909.567601934 2018 40302685.04722431 2019 35388041.15843976 2020 34078904.33329862 2021 45256629.0964623