Year	US Dollars
1980	-70982678.2394
1981	-68654730.3916
1982	-79120356.88492
1983	-73642876.27396
1984	-72514565.0399
1985	-77877459.43816
1986	-110258931.01121
1987	-112061758.78828
1988	-113087674.74937
1989	-114967830.71144
1990	-158624786.34553
1991	-152959920.45709
1992	-176344217.70708
1993	-165686386.41252
1994	-168612423.83168
1995	-210651243.28263
1996	-176152751.79649
1997	-152559146.0206
1998	-189396686.97406
1999	-231143987.5558
2000	-180674415.20431
2001	-183235704.11871
2002	-223549566.60374
2003	-293349947.28923
2004	-347163153.82918
2005	-279823639.93355
2006	-305249322.24658
2007	-457047819.58956
2008	-468670398.58658
2009	-443058204.44435
2010	-484276319.13984
2011	-537268320.90949
2012	-340103469.49048
2013	-265689311.01289
2014	-377647638.67785
2015	-227471262.83014
2016	-344151947.03691
2017	-435191060.93404