Year	current US$
2001	10878000000
2002	11270000000
2003	13402000000
2004	15456000000
2005	16771000000
2006	17891000000
2007	19211000000
2009	20813000000
2010	20884000000
2011	22836000000
2012	22357000000
2013	24507000000
2014	26444000000
2015	15856000000
2016	16522000000
2017	17835000000
2018	20789000000
2019	20998000000
2020	13928000000