Year	Percent
1961	38.34481
1962	38.34481
1963	38.34578
1964	38.34578
1965	38.34578
1966	38.34578
1967	38.34578
1968	38.34578
1969	38.35549
1970	38.35549
1971	38.31668
1972	38.31668
1973	38.30407
1974	38.27496
1975	38.27108
1976	38.27399
1977	38.27496
1978	38.27108
1979	38.27399
1980	38.28854
1981	38.30795
1982	38.32735
1983	38.34675
1984	38.35743
1985	38.37683
1986	38.39624
1987	38.41564
1988	38.43504
1989	38.45445
1990	38.47482
1991	38.48453
1992	38.49617
1993	38.50781
1994	38.52721
1995	38.52721
1996	38.52721
1997	38.52721
1998	38.52721
1999	38.52721
2000	38.52721
2001	38.52721
2002	38.52721
2003	38.52721
2004	38.52721
2005	38.52721
2006	38.52721
2007	38.52721
2008	38.52721
2009	38.52721
2010	38.52721
2011	38.52721
2012	38.52721
2013	38.52721
2014	38.52721
2015	38.52721
2016	38.52721
2017	38.52721
2018	38.52721
2019	38.52721
2020	38.52721
2021	38.52721