Year	Percent
1961	56.4442
1962	56.4442
1963	56.4442
1964	56.4442
1965	56.53613
1966	56.53613
1967	56.53613
1968	56.53613
1969	56.53613
1970	56.53613
1971	52.95091
1972	52.95091
1973	52.95091
1974	52.95091
1975	52.95091
1976	52.95091
1977	52.95091
1978	54.78948
1979	55.70877
1980	55.8007
1981	55.8007
1982	55.8007
1983	55.8007
1984	56.71999
1985	56.81191
1986	56.81191
1987	57.17963
1988	57.7312
1989	57.7312
1990	58.09892
1991	58.55856
1992	58.92627
1993	59.38592
1994	59.75363
1995	60.12135
1996	60.48906
1997	61.22449
1998	61.5922
1999	61.95992
2000	62.51149
2001	62.87921
2002	63.24692
2003	63.61464
2004	63.98235
2005	64.71778
2006	65.63707
2007	66.09671
2008	66.83214
2009	67.19985
2010	67.38371
2011	67.38371
2012	70.78507
2013	70.2335
2014	70.2335
2015	70.2335
2016	70.2335
2017	70.2335
2018	70.2335
2019	70.2335
2020	70.2335
2021	70.2335