Year	constant 2015 US$
1960	-79490000
1961	-130960000
1962	36800000
1963	76700000
1964	164350000
1965	397670000
1966	289130000
1967	330620000
1968	327200000
1969	231690000
1970	329460000
1971	295680000
1972	320100000
1973	422850000
1974	316520000
1975	271750000
1976	281640000
1977	317980000
1978	378950000
1979	469620000
1980	436210000
1981	527480000
1982	427160000
1983	665200000
1984	710960000
1985	689090000
1986	513820000
1987	489870000
1988	438490000
1989	493700000
1990	566110000
1991	764470000
1992	495970000
1993	715210000
1994	432910000
1995	439240000
1996	392980000
1997	517940000
1998	652100000
1999	536800000
2000	474080000
2001	584530000
2002	627420000
2003	599650000
2004	527100000
2005	500160000
2006	493080000
2007	333680000
2008	422490000
2009	411370000
2010	-191890000
2011	523100000
2012	362010000
2013	329810000
2014	299170000
2015	330450000
2016	320200000
2017	-35490000