Year constant 2015 US$ 2010 6258.443193374381 2011 6440.699189700725 2012 6545.506431816962 2013 6549.087223704633 2014 6484.033866564004 2015 6001.667463028593 2016 6201.618321151412 2017 6248.486627243433 2018 6148.471015449001 2019 6078.819127429982 2020 5731.118646020212