Year	Percent
1961	48.86024
1962	48.47614
1963	48.19794
1964	47.93252
1965	47.58979
1966	47.55453
1967	47.52799
1968	47.58128
1969	47.54328
1970	47.42897
1971	47.30886
1972	47.19968
1973	47.07958
1974	46.96581
1975	46.96581
1976	46.96581
1977	46.9847
1978	46.74799
1979	46.74799
1980	46.74799
1981	46.74799
1982	47.10131
1983	47.10131
1984	47.10131
1985	47.10131
1986	47.10131
1987	46.61534
1988	46.61534
1989	46.61534
1990	46.61534
1991	46.61534
1992	46.44949
1993	46.17861
1994	45.98109
1995	45.87191
1996	45.45341
1997	45.29827
1998	45.26584
1999	45.1893
2000	45.23058
2001	45.29007
2002	45.08487
2003	45.08032
2004	45.0758
2005	45.0713
2006	45.06684
2007	45.06235
2008	44.92002
2009	44.70627
2010	44.49251
2011	44.27876
2012	44.065
2013	44.12468
2014	44.18436
2015	44.24403
2016	44.30371
2017	44.36337
2018	44.36337
2019	44.36337
2020	44.36337
2021	44.36337