Year constant 2015 US$ 2011 32577.260790797256 2012 33576.35494535167 2013 38325.48843915081 2014 39320.927452986325 2015 42267.31247004217 2016 44863.59354301265 2017 46078.797665038735 2018 45011.59215693137 2019 47871.415297644104 2020 42230.19010510649 2021 42619.79855271602