Year	Percent
1961	46.34963
1962	46.49232
1963	46.54421
1964	47.16039
1965	48.30194
1966	48.53544
1967	48.60679
1968	48.21762
1969	46.31071
1970	46.52475
1971	46.03181
1972	46.05775
1973	47.21876
1974	46.3626
1975	46.74528
1976	46.32628
1977	46.58702
1978	47.24082
1979	47.13704
1980	48.53674
1981	47.35367
1982	49.9546
1983	47.23044
1984	48.6457
1985	48.15017
1986	46.14337
1987	47.57031
1988	45.85279
1989	46.51826
1990	45.66988
1991	45.75291
1992	45.8956
1993	46.37557
1994	46.42746
1995	46.7336
1996	46.923
1997	47.56771
1998	47.68576
1999	47.68057
2000	47.60533
2001	47.96077
2002	47.84662
2003	47.79213
2004	46.75825
2005	46.65447
2006	46.875
2007	46.71674
2008	45.80869
2009	45.76199
2010	45.71658
2011	46.61685
2012	46.7816
2013	47.0631
2014	47.02677
2015	46.96191
2016	47.72987
2017	48.00099
2018	47.93612
2019	47.11888
2020	47.63776
2021	47.09293