Year	constant 2015 US$
1979	39440000
1980	139800000
1981	1072200000
1982	1225200000
1983	1530690000
1984	1835960000
1985	2182110000
1986	1920910000
1987	2115170000
1988	2739280000
1989	2963270000
1990	2699090000
1991	2484860000
1992	3557560000
1993	3740800000
1994	3416140000
1995	3420510000
1996	2854030000
1997	2465040000
1998	2932540000
1999	2704760000
2000	2077220000
2001	1896160000
2002	1848080000
2003	1492510000
2004	1718430000
2005	1806070000
2006	1303140000
2007	1376030000
2008	1155450000
2009	1019170000
2010	631970000
2011	-515700000
2012	-49330000
2013	-644870000
2014	-955400000
2015	-416330000
2016	-791530000
2017	-1080380000