Year current US$ 2011 453361999.658936 2012 473603143.866887 2013 505393436.9491 2014 536065655.92957 2015 531653248.887801 2016 552103438.338865 2017 536778144.618239 2018 526808620.53353 2019 512328888.302571 2020 428930950.172025 2021 464447539.385473