Year	constant 2015 US$
1960	4890000
1961	50550000
1962	37860000
1963	50680000
1964	17870000
1965	16900000
1966	32850000
1967	38390000
1968	79250000
1969	40570000
1970	39250000
1971	54220000
1972	53830000
1973	63360000
1974	104740000
1975	98500000
1976	57930000
1977	70450000
1978	117340000
1979	74840000
1980	69660000
1981	127390000
1982	112930000
1983	97550000
1984	84120000
1985	65590000
1986	103790000
1987	103220000
1988	88710000
1989	91160000
1990	118300000
1991	89150000
1992	58460000
1993	35380000
1994	20540000
1995	28010000
1996	25520000
1997	55020000
1998	51770000
1999	55860000
2000	29820000
2001	30540000
2002	33880000
2003	-16780000
2004	34510000
2005	35120000
2006	19120000
2007	61640000
2008	90290000
2009	135110000
2010	110890000
2011	155780000
2012	157340000
2013	124640000
2014	36620000
2015	78430000
2016	42340000
2017	11330000