Year	Percent
1960	43.71593
1961	45.38215
1962	42.96866
1963	35.12365
1964	33.27378
1965	31.00664
1966	31.54124
1967	31.59812
1968	31.33851
1969	33.13688
1970	32.58028
1971	28.42619
1972	28.26248
1973	28.93645
1974	32.46534
1975	30.71694
1976	29.40183
1977	28.21446
1978	26.38947
1979	24.87529
1980	23.02727
1981	21.82103
1982	21.50166
1983	20.22309
1984	20.34569
1985	20.28148
1986	20.1845
1987	19.96054
1988	20.07145
1989	18.08178
1990	15.21653
1991	14.3557
1992	14.57241
1993	13.78736
1994	13.66104
1995	12.94944
1996	11.68043
1997	11.10133
1998	13.31224
1999	10.84239
2000	8.59902
2001	8.01097
2002	8.98508
2003	9.30609
2004	9.271
2005	8.26229
2006	8.60998
2007	9.98677
2008	9.96858
2009	9.2191
2010	10.08992
2011	11.45335
2012	9.79375
2013	9.11336
2014	8.87321
2015	8.2875
2016	8.46253
2017	8.59828
2018	7.51209
2019	7.24131
2020	8.166
2021	9.57461
2022	8.92078