Year	constant 2015 US$
1960	26260000
1961	13840000
1962	41960000
1963	70340000
1964	353740000
1965	369450000
1966	335660000
1967	296000000
1968	320040000
1969	288460000
1970	297540000
1971	274830000
1972	287670000
1973	230240000
1974	256440000
1975	288400000
1976	212610000
1977	191730000
1978	251570000
1979	323960000
1980	493220000
1981	534420000
1982	568920000
1983	442760000
1984	385720000
1985	459400000
1986	601210000
1987	552550000
1988	459140000
1989	556980000
1990	557720000
1991	610490000
1992	461580000
1993	466220000
1994	359490000
1995	342100000
1996	411480000
1997	1081690000
1998	631490000
1999	462160000
2000	441520000
2001	532850000
2002	512820000
2003	647300000
2004	1338730000
2005	964960000
2006	809830000
2007	857760000
2008	766230000
2009	405440000
2010	450680000
2011	395950000
2012	335060000
2013	448910000
2014	523670000
2015	679510000
2016	621800000
2017	762890000