Year	constant 2015 US$
1960	270000
1961	2370000
1962	4220000
1963	2570000
1964	2340000
1965	910000
1966	13550000
1967	2730000
1968	2000000
1969	1100000
1970	1550000
1971	5400000
1972	3600000
1973	2830000
1974	2470000
1975	11950000
1976	10730000
1977	11580000
1978	20480000
1979	14940000
1980	46090000
1981	28200000
1982	12130000
1983	24660000
1984	12510000
1985	20380000
1986	31190000
1987	27640000
1988	34900000
1989	40220000
1990	28320000
1991	42140000
1992	44390000
1993	37370000
1994	33700000
1995	61360000
1996	36710000
1997	31550000
1998	30540000
1999	34290000
2000	24050000
2001	32810000
2002	35790000
2003	24950000
2004	30440000
2005	79870000
2006	39780000
2007	35910000
2008	49730000
2009	30040000
2010	99190000
2011	46350000
2012	49300000
2013	18400000
2014	20020000
2015	27620000
2016	27000000
2017	41350000