Year	constant 2015 US$
1960	840000
1961	11000000
1966	10170000
1967	3510000
1968	1330000
1975	2890000
1976	39000000
1977	9320000
1978	10600000
1979	6760000
1980	8230000
1981	13790000
1982	23400000
1983	29450000
1984	29310000
1985	30820000
1986	22510000
1987	28610000
1988	38150000
1989	78560000
1990	81830000
1991	72210000
1992	74360000
1993	61780000
1994	64350000
1995	104270000
1996	57440000
1997	44960000
1998	37870000
1999	38360000
2000	51930000
2001	58250000
2002	37330000
2003	44550000
2004	36110000
2005	34070000
2006	23110000
2007	47420000
2008	41500000
2009	26610000
2010	44730000
2011	62960000
2012	45410000
2013	47400000
2014	36490000
2015	49360000
2016	47040000
2017	39470000