Year	US Dollars
1980	-53408355.2555
1981	-42799980.9369
1982	-40857756.84069
1983	-37754931.20819
1984	-50000800.31491
1985	-37851206.60857
1986	-40707127.86202
1987	-53538033.63347
1988	-49351055.93265
1989	-48503845.70051
1990	-57242550.84707
1991	-44912434.93103
1992	-63379898.56798
1993	-46761515.21294
1994	-50480452.87354
1995	-57517274.2817
1996	-53146014.70052
1997	-52772479.81768
1998	-55792765.3377
1999	-47191855.07388
2000	-10439499.4218
2001	-24653533.63678
2002	-31032935.21424
2003	-41186004.60426
2004	-62562182.33691
2005	-81278802.6733
2006	-95542902.80844
2007	-119865172.73737
2008	-181196000.28703
2009	-175916109.9893
2010	-186722833.80624
2011	-204525938.13277
2012	-231950145.40521
2013	-269311153.85467
2014	-281267015.52325
2015	-166848742.77313
2016	-171446661.58823
2017	-171964049.82558