Year	current US$
2011	18031766459.22565
2012	21808298238.52319
2013	22809878157.513653
2014	24472596621.11234
2015	27683735404.98979
2016	28133098541.884224
2017	27312534537.920837
2018	26566855896.89897
2019	27947788358.112312