Year	constant 2015 US$
1960	72030000
1961	83130000
1962	70500000
1963	50480000
1964	39400000
1965	48450000
1966	60520000
1967	70200000
1968	95610000
1969	107860000
1970	98970000
1971	85120000
1972	60230000
1973	33750000
1974	46340000
1975	36050000
1976	73390000
1977	35180000
1978	82170000
1979	85310000
1980	93680000
1981	149830000
1982	91280000
1983	70710000
1984	54600000
1985	62940000
1986	58230000
1987	49080000
1988	43760000
1989	69560000
1990	230590000
1991	174290000
1992	120370000
1993	145690000
1994	107200000
1995	103180000
1996	170960000
1997	325170000
1998	117810000
1999	113480000
2000	153900000
2001	154060000
2002	95320000
2003	114660000
2004	156980000
2005	160240000
2006	182150000
2007	120900000
2008	149770000
2009	163960000
2010	153640000
2011	133820000
2012	104770000
2013	91050000
2014	128200000
2015	31650000
2016	69900000
2017	50120000