Year	US Dollars
1960	0.72649
1961	0.66273
1962	0.66166
1963	0.43327
1964	0.92045
1965	1.50844
1966	1.33986
1967	1.39713
1968	1.29299
1969	1.56565
1970	1.93524
1971	1.88449
1972	1.42676
1973	1.28143
1974	1.18725
1975	1.2948
1976	0.80144
1977	0.63088
1978	0.58499
1979	0.36381
1980	0.47155
1981	0.52211
1982	0.45162
1983	0.58915
1984	0.39822
1985	0.37937
1986	0.67736
1987	0.76802
1988	1.3069
1989	3.70913
1990	2.67901
1991	2.64441
1992	2.5835
1993	2.80631
1994	1.79847
1995	1.94995
1996	1.70112
1997	1.7562
1998	1.74256
1999	1.2698
2000	1.41471
2001	1.33029
2002	2.31165
2003	2.3276
2004	4.23211
2005	45.56735
2006	79.20722
2007	13.20754
2008	8.48995
2009	10.46791
2010	12.75131
2011	10.93811
2012	11.26656
2013	14.39808
2014	13.81767
2015	13.21519
2016	13.24127
2017	17.3459
2018	16.65064
2019	16.1111
2020	16.20301
2021	15.73181