Year	US Dollars
1973	0.22603
1974	81.71418
1975	36.45644
1976	58.52766
1977	46.78577
1978	47.16438
1979	40.89838
1980	144.09356
1981	88.00317
1982	74.77684
1983	66.43192
1984	85.18169
1985	105.59035
1986	131.53812
1987	179.01338
1988	340.98885
1989	327.86884
1990	199.82281
1991	185.24
1992	197.31051
1993	259.84994
1994	147.85362
1995	91.65688
1996	158.47971
1997	165.61297
1998	151.25481
1999	106.19075
2000	87.76754
2001	220.28444
2002	607.38372
2003	1.93836
2004	-1.71748
2005	55.85875
2006	111.57571
2007	73.16814
2008	992.87471
2009	67.88479
2010	242.17876
2011	331.22465
2012	455.50736
2013	629.09538