Year	Percent
1961	19.7658
1962	19.7658
1963	19.7658
1964	19.7658
1965	19.7658
1966	19.7658
1967	19.7658
1968	19.7658
1969	19.7658
1970	19.7658
1971	19.7658
1972	19.7658
1973	20.18105
1974	20.18105
1975	20.18105
1976	20.18105
1977	20.18105
1978	20.18105
1979	20.18105
1980	20.88697
1981	20.88697
1982	20.88697
1983	20.88697
1984	20.88697
1985	20.88697
1986	20.88697
1987	20.88697
1988	20.88697
1989	20.88697
1990	20.91188
1991	21.01154
1992	21.01154
1993	21.17764
1994	22.00814
1995	22.00814
1996	21.17764
1997	21.17764
1998	21.17764
1999	21.17764
2000	21.17764
2001	21.17764
2002	21.17764
2003	21.17764
2004	21.17764
2005	21.59289
2006	21.59289
2007	21.59289
2008	22.00814
2009	22.17424
2010	22.25729
2011	21.84204
2012	21.84204
2013	21.84204
2014	21.84204
2015	21.84204
2016	21.75899
2017	21.59289
2018	21.59289
2019	21.55137
2020	21.55137
2021	21.55137