Year	constant 2015 US$
1960	136090000
1961	1740460000
1962	1073870000
1963	1396110000
1964	1571390000
1965	1681320000
1966	2129990000
1967	1365660000
1968	1465990000
1969	1044980000
1970	981240000
1971	762490000
1972	697000000
1973	483030000
1974	653530000
1975	580720000
1976	378630000
1977	236120000
1978	266130000
1979	228570000
1980	162710000
1981	519340000
1982	488120000
1983	243890000
1984	391990000
1985	324420000
1986	332600000
1987	433260000
1988	301930000
1989	272470000
1990	193370000
1991	209180000
1992	-448210000
1993	226090000
1994	293810000
1995	283540000
1996	308240000
1997	319470000
1998	347350000
1999	104690000
2000	266670000
2001	319890000
2002	267860000
2003	223130000
2004	155840000
2005	193020000
2006	79340000
2007	276000000
2008	395370000
2009	313070000
2010	414990000
2011	680900000
2012	1141260000
2013	873470000
2014	770220000
2015	996750000
2016	674630000
2017	256430000