Year	constant 2015 US$
1960	180170000
1961	162210000
1962	144850000
1963	153390000
1964	86720000
1965	68040000
1966	78630000
1967	93480000
1968	66640000
1969	86320000
1970	126700000
1971	212370000
1972	320430000
1973	620230000
1974	1196720000
1975	291140000
1976	2440000
1977	1040000
1978	680000
1979	263020000
1980	586580000
1981	252990000
1982	83520000
1983	91260000
1984	53060000
1985	34410000
1986	30660000
1987	29140000
1988	33450000
1989	39550000
1990	60750000
1991	126130000
1992	262420000
1993	393730000
1994	384400000
1995	599060000
1996	489530000
1997	427630000
1998	440430000
1999	357650000
2000	523300000
2001	563820000
2002	652920000
2003	606750000
2004	532240000
2005	576960000
2006	558820000
2007	679580000
2008	692810000
2009	669580000
2010	678010000
2011	683400000
2012	702230000
2013	725110000
2014	728500000
2015	690130000
2016	728410000
2017	830740000