Year	constant 2015 US$
1960	270000
1961	3800000
1962	9970000
1963	17330000
1964	126580000
1965	113710000
1966	107550000
1967	138150000
1968	113810000
1969	126960000
1970	89200000
1971	88970000
1972	130330000
1973	112300000
1974	150420000
1975	182100000
1976	129130000
1977	136220000
1978	131850000
1979	187210000
1980	219370000
1981	226600000
1982	210510000
1983	226510000
1984	334160000
1985	260980000
1986	257040000
1987	293100000
1988	315360000
1989	297580000
1990	342640000
1991	232380000
1992	219440000
1993	217730000
1994	209050000
1995	170990000
1996	186940000
1997	110530000
1998	152080000
1999	150090000
2000	97520000
2001	106670000
2002	79410000
2003	60130000
2004	118410000
2005	95120000
2006	138500000
2007	167320000
2008	238820000
2009	223390000
2010	242840000
2011	229150000
2012	205260000
2013	180250000
2014	537330000
2015	486320000
2016	500960000
2017	497300000