Year	current US$
1990	3000000
1991	118400000
1992	87020000
1993	62350000
1994	57540000
1995	106760000
1996	87600000
1997	76720000
1998	68780000
1999	120270000
2000	81880000
2001	64110000
2002	72960000
2003	66630000
2004	339160000
2005	601040000
2006	714340000
2007	602330000
2008	780360000
2009	707170000
2010	967420000
2011	1273010000
2012	2533300000
2013	3307670000
2014	3591080000
2015	3919140000
2016	6487680000