Year	Percent
1963	37.84047
1964	33.0036
1965	30.30822
1966	29.07268
1967	26.52905
1968	26.40604
1969	24.35656
1970	25.13034
1971	21.56678
1972	22.04363
1973	22.37658
1974	23.33333
1975	23.47084
1976	23.5766
1977	21.40586
1978	20.09399
1979	19.71368
1980	20.28057
1981	17.96402
1982	18.57805
1983	16.6266
1984	13.90065
1985	16.38537
1986	18.95847
1987	20.89578
1988	17.63165
1989	19.64294
1990	17.95793
1991	18.2567
1992	17.57599
1993	17.01226
1994	17.91829
1995	17.17496
1996	17.30718
1997	14.81641
1998	14.37053
1999	16.40492
2000	14.98754
2001	13.01281
2002	13.31091
2003	12.51435
2004	12.3499
2005	12.07433
2006	12.37266
2007	11.88291
2008	10.6975
2009	10.08844
2010	9.3819
2011	9.21772
2012	9.67578
2013	10.11311
2014	8.09852
2015	7.87162
2016	10.66433
2017	10.53183
2018	10.90656
2019	11.29116
2020	14.32461
2021	15.27648
2022	12.64341