Year	constant 2015 US$
1960	1452850000
1961	734600000
1962	1188170000
1963	1362250000
1964	1559970000
1965	817550000
1966	619420000
1967	240670000
1968	232790000
1969	68540000
1970	1045580000
1971	767950000
1972	697830000
1973	3866210000
1974	5386340000
1975	8703960000
1976	8117140000
1977	8161300000
1978	7355770000
1979	3904590000
1980	3266480000
1981	2975510000
1982	3268030000
1983	3182870000
1984	3844230000
1985	3710140000
1986	3162410000
1987	3048460000
1988	2463900000
1989	2712130000
1990	9092480000
1991	7954580000
1992	5181010000
1993	3395430000
1994	3610840000
1995	2436250000
1996	2701430000
1997	2602670000
1998	2642660000
1999	2148220000
2000	1903530000
2001	1822950000
2002	1755530000
2003	1247380000
2004	1713010000
2005	1164390000
2006	950470000
2007	1146610000
2008	1593660000
2009	916860000
2010	551570000
2011	347290000
2012	1573740000
2013	4903440000
2014	3125510000
2015	2486700000
2016	2130330000
2017	-169710000