Year	Percent
1961	38.01587
1962	38.01587
1963	38.01587
1964	38.01587
1965	38.01587
1966	38.01587
1967	38.01587
1968	38.01587
1969	38.01587
1970	38.01587
1971	38.01587
1972	38.01587
1973	38.02381
1974	38.04382
1975	38.11944
1976	38.19886
1977	38.19886
1978	38.23856
1979	38.23856
1980	38.23856
1981	38.23856
1982	38.23856
1983	38.23856
1984	38.23856
1985	38.24253
1986	38.28224
1987	38.28224
1988	38.3021
1989	38.31798
1990	38.35769
1991	38.3974
1992	38.41328
1993	38.4371
1994	38.45299
1995	38.47681
1996	38.46093
1997	38.61976
1998	38.61976
1999	38.61976
2000	38.61976
2001	38.69917
2002	38.69917
2003	38.77859
2004	38.77859
2005	38.85801
2006	38.85801
2007	38.8588
2008	38.8588
2009	38.94139
2010	39.10022
2011	39.17964
2012	39.45759
2013	39.73634
2014	39.89517
2015	39.89597
2016	39.97618
2017	39.97618
2018	39.97618
2019	39.97618
2020	39.97618
2021	39.97618