Year	constant 2015 US$
1961	8820000
1966	21970000
1967	4710000
1969	830000
1971	1250000
1973	40000
1974	39530000
1975	69020000
1976	78220000
1977	116350000
1978	131060000
1979	118590000
1980	119580000
1981	143980000
1982	149930000
1983	154270000
1984	141910000
1985	140290000
1986	136750000
1987	187890000
1988	159150000
1989	193000000
1990	180740000
1991	155600000
1992	138740000
1993	127920000
1994	246160000
1995	137550000
1996	221330000
1997	163110000
1998	126860000
1999	72270000
2000	122290000
2001	93280000
2002	85040000
2003	173400000
2004	83800000
2005	70140000
2006	89340000
2007	115600000
2008	115840000
2009	131300000
2010	117670000
2011	102770000
2012	73390000
2013	94430000
2014	98120000
2015	95590000
2016	196820000
2017	111320000