Year	US Dollars
1977	-16029629.62963
1978	-11088888.88889
1979	-23662962.96296
1980	-30166666.66667
1981	-23259259.25926
1982	-25474074.07407
1983	-22862962.96296
1984	-14329629.62963
1985	-6459259.25926
1986	-9485185.18519
1987	-22711111.11111
1988	-11781481.48148
1989	-46725925.92593
1990	-22100000
1991	-41507407.40741
1992	-23722222.22222
1993	-43440740.74074
1994	-57814814.81481
1995	-38200000
1996	-37051851.85185
1997	-80603703.7037
1998	-91600000
1999	-62785185.18519
2000	-21055555.55556
2001	-33515555.55556
2002	-36506074.07407
2003	-68543370.37037
2004	-87677592.59259
2005	-90648925.92593
2006	-113858851.85185
2007	-189895481.48148
2008	-220648888.88889
2009	-195735925.92593
2010	-205991740.74074
2011	-193824703.7037
2012	-210725925.92593
2013	-236455074.07407
2014	-225974814.81481
2015	-132222222.22222
2016	-127407407.40741
2017	-114814814.81481