Year	constant 2015 US$
1960	124290000
1961	109030000
1962	183270000
1963	24690000
1964	31920000
1965	24660000
1966	137010000
1967	40310000
1968	35020000
1969	69680000
1970	133190000
1971	121130000
1972	274200000
1973	1854720000
1974	3034050000
1975	2865760000
1976	2652600000
1977	3187700000
1978	2476300000
1979	4909900000
1980	4196380000
1981	4087000000
1982	2664390000
1983	2056250000
1984	1523010000
1985	1432780000
1986	1397080000
1987	1301450000
1988	248560000
1989	181130000
1990	1238490000
1991	694180000
1992	247950000
1993	306790000
1994	791930000
1995	359190000
1996	242700000
1997	232460000
1998	189910000
1999	248500000
2000	191030000
2001	235650000
2002	82280000
2003	140610000
2004	115100000
2005	76530000
2006	17590000
2007	69840000
2008	133670000
2009	187720000
2010	123070000
2011	283270000
2012	1402720000
2013	3143920000
2014	3652950000
2015	4817170000
2016	8899750000
2017	11154560000