Year	US Dollars
1960	0.21396
1961	2.26233
1962	0.95985
1963	0.07653
1964	-0.54991
1965	1.14535
1966	0.81982
1967	0.78893
1968	0.57494
1969	0.44484
1970	0.59516
1971	0.3241
1972	0.39594
1973	0.23919
1974	0.38739
1975	0.36836
1976	0.33861
1977	0.29729
1978	0.27073
1979	1.01845
1980	0.99534
1981	1.60861
1982	2.12407
1983	2.07768
1984	1.27229
1985	2.01597
1986	3.5343
1987	2.27585
1988	2.25904
1989	1.42733
1990	2.18232
1991	3.48188
1992	3.99079
1993	5.15197
1994	5.09792
1995	4.56332
1996	3.33488
1997	1.22125
1998	0.31699
1999	0.47698
2000	-0.41339
2001	0.99543
2002	1.34318
2003	1.12897
2004	1.3077
2005	1.89677
2006	2.30056
2007	1.03838
2008	1.35206
2009	1.68105
2010	4.04088
2011	8.47145
2012	3.52405
2013	4.79484
2014	6.86189
2015	2.67225
2016	6.66018
2017	6.14307
2018	4.42862
2019	4.19746
2020	6.29953
2021	4.42942