Year	Percent
1961	52.53043
1962	52.90554
1963	53.02452
1964	52.97911
1965	53.29246
1966	53.37875
1967	53.45141
1968	53.5604
1969	53.7693
1970	53.72389
1971	53.89646
1972	54.06903
1973	54.02361
1974	53.9782
1975	53.93279
1976	53.88738
1977	53.86921
1978	53.85014
1979	53.83924
1980	53.6921
1981	53.46049
1982	53.22888
1983	52.99546
1984	52.57947
1985	52.39782
1986	52.1208
1987	51.79837
1988	51.56676
1989	51.33515
1990	51.14623
1991	51.00636
1992	50.95822
1993	30.54
1994	30.472
1995	30.5
1996	30.5
1997	30.492
1998	30.449
1999	30.557
2000	30.534
2001	30.559
2002	30.498
2003	31.607
2004	29.32933
2005	29.76343
2006	30.31951
2007	31.07924
2008	30.58122
2009	30.99889
2010	31.61786
2011	32.18678
2012	32.33084
2013	32.51808
2014	32.70602
2015	32.89296
2016	33.07937
2017	33.26393
2018	33.58523
2019	33.83926
2020	34.09275
2021	34.19811