Year	Percent
1965	27.2864
1966	26.60845
1967	26.89222
1968	26.85938
1969	25.86728
1970	25.08737
1971	23.51911
1972	24.1306
1973	24.12897
1974	24.3821
1975	23.88647
1976	23.62861
1977	25.04703
1978	23.04046
1979	21.46588
1980	19.3599
1981	19.24774
1982	18.76512
1983	18.7139
1984	17.40893
1985	16.99069
1986	17.47693
1987	18.06374
1988	16.74929
1989	16.05719
1990	17.06678
1991	17.4548
1992	16.79394
1993	14.96783
1994	14.83154
1995	14.01807
1996	12.76882
1997	12.60647
1998	13.23579
1999	13.00077
2000	8.30572
2001	8.32097
2002	8.51001
2003	8.32877
2004	7.91098
2005	7.52727
2006	7.18677
2007	6.93456
2008	6.68738
2009	6.68974
2010	6.32485
2011	6.0917
2012	5.58269
2013	5.39271
2014	5.44696
2015	5.98042
2016	6.60641
2017	6.38966
2018	6.22571
2019	6.41072
2020	7.46616
2021	7.63534
2022	8.30463