Year	US Dollars
1970	562587510.50126
1971	798585572.843
1972	635325923.70081
1973	1115219544.40409
1974	3393498137.4873
1975	1312902133.42364
1976	3809685066.03454
1977	3048086691.50017
1978	5947511005.75686
1979	11832712495.767
1980	17049779884.8629
1981	-11786318997.6295
1982	-17075041876.0469
1983	-3373753618.52686
1984	-1872306207.78385
1985	-2255709231.26407
1986	-4682534577.03441
1987	-1644580250.88453
1988	-1953039562.56031
1989	-594081698.29527
1990	486330009.6494
2004	-2817476830.35069
2005	-3520220788.04348
2006	8086103286.13542
2007	15730752406.0887
2008	25797687386.9578
2009	125999999.99999
2010	7391500000
2011	30952800000
2012	33459838117.4835
2013	8600000000
2014	10300000000
2015	-10787664499.9333
2016	-14366787716.1668
2017	2596631128.74782