Year	Percent
1961	43.72294
1962	43.50649
1963	43.83117
1964	43.61472
1965	43.50649
1966	43.29004
1967	43.39827
1968	43.39827
1969	43.18182
1970	43.07359
1971	42.85714
1972	42.64069
1973	42.66234
1974	31.06061
1975	19.51299
1976	19.25325
1977	19.05844
1978	18.86364
1979	18.66883
1980	18.56061
1981	19.0368
1982	19.69697
1983	19.80519
1984	19.69697
1985	17.61905
1986	17.66234
1987	17.57576
1988	17.46753
1989	17.46753
1990	17.38095
1991	17.22944
1992	17.27273
1993	17.17532
1994	15.51948
1995	15.48701
1996	15.49784
1997	15.38961
1998	15.60606
1999	15.60606
2000	15.31385
2001	15.15152
2002	15.15152
2003	16.66667
2004	16.88312
2005	18.07359
2006	16.99134
2007	15.93074
2008	12.51082
2009	13.80952
2010	12.39177
2011	12.58658
2012	12.65152
2013	11.77814
2014	11.79437
2015	13.70996
2016	11.83874
2017	13.14069
2018	14.33408
2019	13.56368
2020	13.81486
2021	13.32629