Year	Percent
1961	33.47136
1962	32.7253
1963	33.07536
1964	26.86147
1965	24.89817
1966	24.95416
1967	25.08643
1968	23.8359
1969	20.12031
1970	22.6738
1971	21.72236
1972	21.33072
1973	28.81368
1974	25.73867
1975	21.96473
1976	21.02539
1977	21.924
1978	23.47426
1979	21.78005
1980	23.50669
1981	24.18612
1982	24.73758
1983	24.86187
1984	21.06454
1985	16.50132
1986	19.65137
1987	23.89214
1988	24.11613
1989	23.76912
1990	21.88607
1991	28.59169
1992	28.54554
1993	28.64726
1994	27.93854
1995	28.13398
1996	27.19803
1997	25.04665
1998	25.94134
1999	26.27666
2000	24.82875
2001	24.86896
2002	24.23002
2003	24.17885
2004	22.9179
2005	20.0702
2006	16.60714
2007	18.43252
2008	18.55942
2009	19.17818
2010	16.73305
2011	14.51589
2012	16.08596
2013	16.2826
2014	18.81421
2015	20.62975
2016	21.73917
2017	22.71875
2018	23.65597
2019	19.95788
2020	19.15234
2021	19.14858
2022	22.23099