Year	Percent
1961	4.39276
1962	4.39276
1963	4.39276
1964	4.39276
1965	4.39276
1966	4.39276
1967	4.39276
1968	4.39276
1969	4.39276
1970	4.39276
1971	4.39276
1972	4.39276
1973	4.39276
1974	4.4789
1975	4.4789
1976	4.4789
1977	4.4789
1978	4.4789
1979	4.56503
1980	4.7373
1981	4.82343
1982	4.90956
1983	4.99569
1984	5.08183
1985	5.08183
1986	5.16796
1987	5.25409
1988	5.25409
1989	5.16796
1990	5.25409
1991	5.25409
1992	5.51249
1993	5.59862
1994	5.59862
1995	5.59862
1996	5.68475
1997	5.68475
1998	5.68475
1999	5.68475
2000	5.68475
2001	5.71059
2002	5.65891
2003	5.70198
2004	5.61585
2005	5.56417
2006	5.62446
2007	5.68475
2008	5.74505
2009	5.80534
2010	5.86563
2011	5.92593
2012	5.98622
2013	6.04651
2014	6.17929
2015	6.17929
2016	6.17929
2017	6.26632
2018	6.44038
2019	6.44038
2020	6.44038
2021	6.44038