Year	US Dollars
1960	-411824000
1961	-311912000
1962	-234024000
1963	-277032000
1964	-445848000
1965	-412432000
1966	-375216000
1967	-568840000
1968	-679896000
1969	-560120000
1970	-675968000
1971	-422920000
1972	-347920000
1973	-581984000
1974	-1557920000
1975	-2398560000
1976	-1226253246.75325
1977	79274336.28319
1978	-583017543.85965
1979	-1697885964.91228
1980	-4409217391.30435
1981	-6319551020.40816
1982	8713031914.89362
1983	14263530391.3405
1984	13749350417.1633
1985	9373160762.94278
1986	5056577312.84734
1987	8573316644.89914
1988	2545785931.1073
1989	-144467194.79992
1990	-2901885444.0731
1991	-9143001921.54784
1992	-18303168438.3987
1993	-16350614327.8983
1994	-20818300494.8002
1995	7119984422.22014
1996	6537922467.56323
1997	-557966028.91962
1998	-9515241790.71804
1999	-8119178067.86327
2000	-11462764922.374
2001	-13867631739.5074
2002	-12299152444.0762
2003	-10829244600.9825
2004	-12481021088.0737
2005	-14070670496.1506
2006	-14068992219.6124
2007	-18325416720.0454
2008	-26351576322.8119
2009	-14920691752.6918
2010	-14438870607.7873
2011	-16482747096.1822
2012	-14846796993.0521
2013	-14701602254.9327
2014	-15493812074.4781
2015	-23876138513.279
2016	-21305578163.426
2017	-20760337786.79389