Year	constant 2015 US$
1960	122860000
1961	166590000
1962	162760000
1963	91760000
1964	133360000
1965	168760000
1966	201890000
1967	155550000
1968	239920000
1969	225160000
1970	174760000
1971	260970000
1972	275260000
1973	206940000
1974	279930000
1975	369160000
1976	225460000
1977	226830000
1978	195730000
1979	288460000
1980	292860000
1981	326020000
1982	312570000
1983	408860000
1984	725320000
1985	536570000
1986	397930000
1987	526760000
1988	166660000
1989	194200000
1990	595860000
1991	347170000
1992	227470000
1993	160340000
1994	94290000
1995	110950000
1996	-392650000
1997	-226370000
1998	221300000
1999	146680000
2000	60200000
2001	38760000
2002	109520000
2003	117990000
2004	288980000
2005	31230000
2006	249200000
2007	220770000
2008	145880000
2009	125940000
2010	3140000
2011	39220000
2012	18040000
2013	-107790000
2014	14580000
2015	-6930000
2016	-51820000
2017	-32780000