Year	constant 2015 US$
1960	100600000
1961	88350000
1962	58620000
1963	75300000
1964	76630000
1965	94190000
1966	65510000
1967	105930000
1968	94440000
1969	98020000
1970	117810000
1971	99290000
1972	126820000
1973	113290000
1974	101670000
1975	138570000
1976	217720000
1977	190500000
1978	193790000
1979	163870000
1980	163570000
1981	172070000
1982	145140000
1983	167620000
1984	146440000
1985	177740000
1986	258530000
1987	428740000
1988	399400000
1989	439870000
1990	304840000
1991	283620000
1992	281470000
1993	286680000
1994	278300000
1995	241050000
1996	218500000
1997	340990000
1998	309410000
1999	375690000
2000	343680000
2001	313620000
2002	339590000
2003	295560000
2004	238720000
2005	268480000
2006	489300000
2007	408750000
2008	458360000
2009	345680000
2010	361860000
2011	338280000
2012	281540000
2013	452160000
2014	258840000
2015	411450000
2016	265450000
2017	358490000