Year	constant 2015 US$
1960	69030000
1961	65400000
1962	94320000
1963	51660000
1964	65930000
1965	38150000
1966	65730000
1967	75660000
1968	91020000
1969	101420000
1970	113370000
1971	127780000
1972	136420000
1973	122960000
1974	150760000
1975	162050000
1976	149790000
1977	141970000
1978	190100000
1979	214670000
1980	244140000
1981	284190000
1982	301310000
1983	337160000
1984	348080000
1985	352010000
1986	382360000
1987	326960000
1988	315370000
1989	330630000
1990	369940000
1991	350610000
1992	398130000
1993	288360000
1994	395150000
1995	333120000
1996	133040000
1997	75140000
1998	93580000
1999	104130000
2000	135440000
2001	212990000
2002	241760000
2003	276920000
2004	392500000
2005	391040000
2006	445250000
2007	470850000
2008	460640000
2009	527560000
2010	577960000
2011	499790000
2012	472360000
2013	496800000
2014	456400000
2015	367190000
2016	742470000
2017	418980000