Year	Percent
1961	6.71577
1962	6.71577
1963	6.49913
1964	6.2825
1965	6.2825
1966	6.32582
1967	6.32582
1968	6.36915
1969	6.37782
1970	6.39948
1971	6.42114
1972	6.55113
1973	6.63778
1974	6.73744
1975	6.79376
1976	6.84575
1977	6.88908
1978	6.92374
1979	6.95407
1980	6.95841
1981	6.9714
1982	7.00607
1983	7.01906
1984	7.06239
1985	7.08406
1986	7.09705
1987	7.10572
1988	7.14905
1989	7.15771
1990	7.19237
1991	7.20104
1992	7.20971
1993	7.21404
1994	7.32236
1995	7.36568
1996	7.36568
1997	7.60832
1998	7.64731
1999	7.68198
2000	7.82496
2001	7.9766
2002	8.12825
2003	8.2799
2004	8.43154
2005	8.60052
2006	8.77383
2007	8.93847
2008	9.11612
2009	9.39341
2010	9.61872
2011	9.86352
2012	9.99675
2013	10.11698
2014	10.11698
2015	10.11698
2016	10.11698
2017	9.78726
2018	9.45754
2019	9.12782
2020	8.79983
2021	8.79983