Year	US Dollars
1960	4200000000
1961	4900000000
1962	4100000000
1963	5000000000
1964	6900000000
1965	5600000000
1966	3800000000
1967	3600000000
1968	1300000000
1969	1400000000
1970	3950000000
1971	622000000
1972	-3372000000
1973	4111000000
1974	-814000000
1975	15978000000
1976	-1631000000
1977	-23093000000
1978	-25366000000
1979	-22546000000
1980	-13056000000
1981	-12520000000
1982	-19974000000
1983	-51642000000
1984	-102724000000
1985	-114019000000
1986	-131867000000
1987	-144769999999.99997
1988	-109392000000
1989	-86740999999.99998
1990	-77855000000.00002
1991	-28615000000
1992	-34740000000
1993	-65174000000
1994	-92486000000
1995	-89758000000
1996	-96376000000
1997	-101970000000
1998	-162709000000
1999	-256631000000
2000	-375795000000
2001	-368683000000.00006
2002	-426464000000
2003	-503655000000.00006
2004	-619170000000
2005	-721185000000
2006	-770947000000
2007	-718542000000.00012
2008	-723067000000
2009	-395436000000
2010	-512657000000
2011	-579995000000
2012	-565661800000
2013	-492005000000
2014	-509509000000
2015	-524042000000
2016	-521239000000.00006