Year	US Dollars
1974	780499815.33916
1975	778475941.46671
1976	1072931843.93719
1977	1360990407.47725
1978	1563764291.99648
1979	2268923020.32558
1980	4026713992.15393
1981	3468074028.49434
1982	3075233644.85981
1983	2663984855.65547
1989	794236784.0845
1990	864000000
1991	981129891.17851
1992	416820135.05218
1993	123158806.78302
1994	109336126.75134
1995	184139974.60138
1996	-36170212.76596
1997	-68022629.31034
1998	-280831739.96176
1999	341002949.85251
2000	1892586020.88167
2001	1698908299.38048
2002	1489797162.96214
2003	2184905751.34887
2004	2913434268.13395
2005	4086996695.50589
2006	5334822833.40676
2007	4893570433.28246
2008	7295088907.70533
2009	3970301113.70824
2010	5407407407.40741
2011	7312981954.0504
2012	6606113956.46607
2013	4550031969.30946
2014	6509076558.80032
2015	2524547239.79926
2016	1349353247.31774
2017	1694264033.78473