Year	Percent
1961	45.33223
1962	45.64272
1963	45.95322
1964	46.26371
1965	46.57421
1966	46.8847
1967	47.1952
1968	47.40219
1969	48.23018
1970	48.33368
1971	48.51998
1972	49.05817
1973	49.78265
1974	50.19665
1975	50.81764
1976	51.95612
1977	52.57711
1978	53.0946
1979	53.61209
1980	54.23308
1981	54.33658
1982	54.44007
1983	54.44007
1984	54.44007
1985	54.44007
1986	54.58497
1987	54.58497
1988	54.58497
1989	54.66777
1990	52.7013
1991	52.7013
1992	52.7013
1993	52.7013
1994	52.7013
1995	53.32229
1996	53.30159
1997	51.74912
1998	51.95612
1999	51.06603
2000	52.05961
2001	52.05961
2002	52.05961
2003	50.40364
2004	50.03105
2005	50.03105
2006	50.03105
2007	50.03105
2008	49.61706
2009	49.61706
2010	49.61706
2011	49.61706
2012	48.68557
2013	48.68557
2014	48.68557
2015	50.27945
2016	50.27945
2017	50.27945
2018	50.27945
2019	51.10349
2020	51.10349
2021	51.10349