Year	US Dollars
1960	26.3789
1961	23.316
1962	11.12574
1963	14.16681
1964	20.29273
1965	32.63158
1966	19.0969
1967	44.87989
1968	48.10889
1969	24.63477
1970	75
1971	141.51202
1972	155.63369
1973	140.44153
1974	147.22888
1975	126.1553
1976	122.30596
1977	176.25353
1978	263.39503
1979	400.88695
1980	339.86184
1981	262.82502
1982	280.99918
1983	238.28398
1984	232.24191
1985	337.80885
1986	434.7164
1987	352.55989
1988	299.76003
1989	282.79381
1990	511.60317
1991	322.83252
1992	274.86117
1993	273.20665
1994	176.13368
1995	175.15669
1996	252.03816
1997	222.45503
1998	308.82988
1999	165.65103
2000	290.88758
2001	165.14371
2002	691.92456
2003	113.43183
2004	128.88754
2005	207.58407
2006	162.05674
2007	71.50165
2008	86.13551
2009	265.29817
2010	600.75749
2011	259.83234
2012	393.53136
2013	304.83941
2014	131.34995
2015	72.57624
2016	61.26092
2017	169.02644