Year	Percent
1961	49.30818
1962	49.93711
1963	49.93711
1964	50.25157
1965	50.56604
1966	50.56604
1967	50.78616
1968	50.78616
1969	50.9434
1970	50.9434
1971	51.25786
1972	51.28931
1973	51.69811
1974	52.27987
1975	52.56289
1976	52.95597
1977	53.71069
1978	54.1195
1979	54.16667
1980	54.26101
1981	54.62264
1982	55
1983	55.2956
1984	56.29245
1985	57.16981
1986	57.48428
1987	57.86164
1988	58.86792
1989	59.18239
1990	59.5283
1991	59.59119
1992	60.37736
1993	61.32704
1994	61.94969
1995	62.26415
1996	62.26415
1997	61.94969
1998	61.94969
1999	61.63522
2000	61.63522
2001	61.63522
2002	61.63522
2003	61.63522
2004	62.89308
2005	63.52201
2006	63.83648
2007	64.77987
2008	64.77987
2009	64.77987
2010	64.77987
2011	64.77987
2012	65.09434
2013	66.66667
2014	67.13836
2015	69.81132
2016	68.86792
2017	69.18239
2018	72.79874
2019	73.05031
2020	73.27044
2021	73.89937