Year	Percent
1962	37.00273
1963	38.19772
1964	37.57483
1965	36.70829
1966	35.68362
1967	32.89624
1968	32.49111
1969	32.55389
1970	32.06578
1971	33.19839
1972	34.46372
1973	37.70179
1974	35.2972
1975	36.90631
1976	34.55007
1977	34.11264
1978	32.06745
1979	31.39573
1980	29.4646
1981	27.76733
1982	25.8663
1983	24.78704
1984	26.41779
1985	25.54799
1986	22.70748
1987	21.63663
1988	22.58075
1989	21.11037
1990	18.60194
1991	16.00124
1992	14.94896
1993	16.71891
1994	18.16377
1995	18.44378
1996	18.36501
1997	16.42797
1998	14.80094
1999	14.00456
2000	12.85666
2001	11.37332
2002	11.00964
2003	13.00894
2004	13.93335
2005	12.71395
2006	11.7936
2007	12.70973
2008	13.41765
2009	9.94794
2010	13.01448
2011	13.79623
2012	10.04223
2013	12.86484
2014	11.77086
2015	9.44042
2016	10.69651
2017	10.18482
2018	9.9502
2019	9.66747
2020	10.72799
2021	11.2789
2022	10.99879