Year	constant 2015 US$
1960	14790000
1961	38170000
1962	52410000
1963	49400000
1964	48100000
1965	75770000
1966	93680000
1967	100630000
1968	102380000
1969	93480000
1970	55440000
1971	95260000
1972	73460000
1973	65470000
1974	86020000
1975	103910000
1976	95460000
1977	115300000
1978	140810000
1979	159950000
1980	203230000
1981	235920000
1982	213960000
1983	248080000
1984	234350000
1985	219070000
1986	168240000
1987	179290000
1988	177960000
1989	216790000
1990	196160000
1991	169180000
1992	186190000
1993	197080000
1994	152250000
1995	134690000
1996	121480000
1997	117420000
1998	79360000
1999	41310000
2000	54030000
2001	78250000
2002	103940000
2003	91570000
2004	101140000
2005	69840000
2006	70980000
2007	123750000
2008	129480000
2009	115050000
2010	244580000
2011	240570000
2012	268390000
2013	309790000
2014	100460000
2015	83490000
2016	112320000
2017	144240000