Year	constant 2015 US$
1960	114510000
1961	738450000
1962	963380000
1963	933760000
1964	846630000
1965	677130000
1966	877840000
1967	658360000
1968	506560000
1969	538380000
1970	389540000
1971	260760000
1972	245200000
1973	209180000
1974	92700000
1975	445730000
1976	27700000
1977	34180000
1978	23360000
1979	-71970000
1980	-27930000
1981	-16570000
1982	-14860000
1983	6990000
1984	14710000
1985	100440000
1986	-9310000
1987	25000000
1988	61120000
1989	93180000
1990	132080000
1991	154010000
1992	152400000
1993	222240000
1994	174900000
1995	138700000
1996	209600000
1997	151640000
1998	128620000
1999	82350000
2000	63120000
2001	81590000
2002	7710000
2003	93850000
2004	62060000
2005	177940000
2006	99970000
2007	98800000
2008	88610000
2009	69650000
2010	170570000
2011	144410000
2012	108070000
2013	68930000
2014	212190000
2015	53990000
2016	178440000
2017	67920000