Year	US Dollars
1960	1.26842
1961	5.9044
1962	2.49546
1963	1.17588
1964	0.1783
1965	0.86837
1966	0.44648
1967	1.22946
1968	0.31181
1969	0.61642
1970	0.73639
1971	0.25791
1972	0.2949
1973	-0.12072
1974	0.28468
1975	0.04626
1976	-0.16134
1977	1.10934
1978	6.75258
1979	0.15697
1980	0.73104
1981	0.11958
1982	-0.01482
1983	0.97029
1984	0.17095
1985	0.24182
1986	0.53789
1987	1.40241
1988	1.56068
1989	1.70175
1990	1.90792
1991	3.33501
1992	1.7803
1993	2.35092
1994	2.16785
1995	3.07493
1996	2.67052
1997	3.21316
1998	2.59307
1999	2.5047
2000	1.98141
2001	1.71819
2002	1.70125
2003	1.92849
2004	2.73162
2005	1.4344
2006	1.64488
2007	1.43488
2008	1.37032
2009	1.24551
2010	1.49176
2011	1.38572
2012	1.96303
2013	1.67744
2014	1.01511
2015	1.3559
2016	1.39473
2017	1.66002
2018	1.94423
2019	2.36172
2020	2.69354
2021	3.45494