Year	Percent
1961	57.01754
1962	57.01754
1963	56.49123
1964	55.78947
1965	56.14035
1966	54.38596
1967	54.5614
1968	54.73684
1969	55.4386
1970	55.4386
1971	55.4386
1972	56.14035
1973	56.84211
1974	57.54386
1975	58.24561
1976	59.12281
1977	59.82456
1978	60.52632
1979	61.22807
1980	62.10526
1981	62.80702
1982	63.68421
1983	64.21053
1984	64.91228
1985	65.61404
1986	66.49123
1987	67.19298
1988	67.89474
1989	68.59649
1990	69.47368
1991	70.17544
1992	70.87719
1993	71.57895
1994	72.45614
1995	73.15789
1996	73.85965
1997	74.5614
1998	75.4386
1999	76.14035
2000	76.84211
2001	77.54386
2002	79.64912
2003	80.29825
2004	80.35088
2005	80.89474
2006	74.31579
2007	73.89474
2008	77.68421
2009	76.17544
2010	76.10526
2011	74.75439
2012	67.36842
2013	68.07018
2014	68.24561
2015	70.87719
2016	71.40351
2017	70.52632
2018	70.70175
2019	70.70175
2020	69.82456
2021	68.77193