Year	constant 2015 US$
1960	370000
1961	17310000
1962	36360000
1963	34410000
1964	106750000
1965	102680000
1966	152150000
1967	149320000
1968	196020000
1969	207000000
1970	190500000
1971	226530000
1972	217140000
1973	316720000
1974	540940000
1975	462920000
1976	430970000
1977	295800000
1978	413940000
1979	396700000
1980	344840000
1981	437360000
1982	603070000
1983	419700000
1984	396650000
1985	709740000
1986	601440000
1987	595460000
1988	576620000
1989	484570000
1990	539780000
1991	506580000
1992	456580000
1993	446170000
1994	462330000
1995	317590000
1996	296490000
1997	429020000
1998	380680000
1999	245610000
2000	293930000
2001	378710000
2002	409100000
2003	569510000
2004	587000000
2005	554210000
2006	558700000
2007	547910000
2008	546400000
2009	430020000
2010	688830000
2011	569400000
2012	808140000
2013	709570000
2014	815060000
2015	870550000
2016	951380000
2017	1181590000