Year	constant 2015 US$
1961	93210000
1962	106680000
1963	22400000
1964	25990000
1965	70270000
1966	67360000
1967	59240000
1968	109220000
1969	86880000
1970	58570000
1971	118240000
1972	84520000
1973	83320000
1974	105030000
1975	83790000
1976	85720000
1977	100460000
1978	349390000
1979	296740000
1980	270430000
1981	351910000
1982	398460000
1983	392090000
1984	370270000
1985	353960000
1986	341910000
1987	300980000
1988	317220000
1989	419990000
1990	396920000
1991	219830000
1992	173040000
1993	150430000
1994	162610000
1995	135260000
1996	66350000
1997	87810000
1998	22520000
1999	-26540000
2000	23840000
2001	86310000
2002	36370000
2003	10250000
2004	91340000
2005	43610000
2006	36560000
2007	22590000
2008	71870000
2009	133010000
2010	125220000
2011	36410000
2012	28280000
2013	62420000
2014	82050000
2015	56580000
2016	26850000
2017	57710000