Year	US Dollars
1960	5.51766
1961	5.37049
1962	7.8857
1963	9.84855
1964	10.09483
1965	9.62277
1966	7.06512
1967	8.87831
1968	6.96057
1969	5.6853
1970	7.09772
1971	6.99817
1972	4.87493
1973	4.39212
1974	7.08278
1975	10.73099
1976	14.35607
1977	8.18856
1978	8.44599
1979	9.07382
1980	14.39049
1981	9.52068
1982	9.8991
1983	7.27753
1984	6.64505
1985	6.8787
1986	8.03103
1987	6.39955
1988	10.78979
1989	10.68788
1990	7.87244
1991	9.58889
1992	6.91913
1993	6.57971
1994	9.18549
1995	3.76089
1996	5.00784
1997	4.8272
1998	5.67481
1999	4.09922
2000	3.56041
2001	11.21201
2002	11.95343
2003	6.25132
2004	7.7792
2005	8.46867
2006	11.56573
2007	11.01501
2008	5.70144
2009	13.32226
2010	15.0843
2011	18.70246
2012	9.97701
2013	10.68713
2014	17.36275
2015	17.84155
2016	13.86775
2017	10.92667
2018	6.3122
2019	9.00036
2020	11.40549
2021	11.66065