Year	constant 2015 US$
1990	4075000
1991	163559000
1992	120625000
1993	82126000
1994	99452000
1995	151164000
1996	124074000
1997	111616000
1998	97875000
1999	178544000
2000	121367000
2001	122319000
2002	124716000
2003	91729000
2004	395653000
2005	613605000
2006	711781000
2007	513617000
2008	598137000
2009	608134000
2010	763370000
2011	1031735000
2012	2058349000
2013	2691418000
2014	3101314000
2015	3919140000
2016	6738692000