Year	constant 2015 US$
1966	40480000
1967	62550000
1968	50760000
1969	38670000
1970	48720000
1971	51040000
1972	50510000
1973	71950000
1974	106860000
1975	68820000
1976	83010000
1977	39260000
1978	37600000
1979	45760000
1980	91030000
1981	104780000
1982	89690000
1983	89340000
1984	106180000
1985	116790000
1986	89130000
1987	88280000
1988	79130000
1989	69260000
1990	60550000
1991	85730000
1992	60060000
1993	61770000
1994	48740000
1995	45660000
1996	45100000
1997	38390000
1998	51430000
1999	28680000
2000	28360000
2001	40370000
2002	38070000
2003	28930000
2004	27310000
2005	23870000
2006	31910000
2007	40960000
2008	35390000
2009	43880000
2010	63770000
2011	46800000
2012	89990000
2013	71020000
2014	65730000
2015	66230000
2016	53750000
2017	65630000