Year	Percent
1960	15.7324
1961	15.07757
1962	16.09562
1963	14.95273
1964	16.02574
1965	16.17306
1966	12.74069
1967	12.80607
1968	11.80744
1969	11.16166
1970	10.3736
1971	11.0896
1972	11.08868
1973	10.85527
1974	10.75257
1975	10.22841
1976	11.41798
1977	12.91817
1978	10.3034
1979	10.06231
1980	9.85064
1981	9.84352
1982	8.37088
1983	10.53331
1984	11.59576
1985	11.10461
1986	10.3813
1987	9.35991
1988	9.79656
1989	8.44159
1990	6.96344
1991	6.84139
1992	6.80608
1993	6.77811
1994	8.72199
1995	5.01167
1996	4.76841
1997	4.68505
1998	4.75004
1999	4.64598
2000	4.75046
2001	4.80104
2002	5.47527
2003	6.16718
2004	5.66531
2005	4.65117
2006	4.37004
2007	4.41692
2008	4.56785
2009	4.47677
2010	4.11576
2011	4.34203
2012	4.16833
2013	4.50689
2014	4.32561
2015	4.31915
2016	4.89135
2017	4.60059
2018	4.4204
2019	4.20501
2020	5.71149
2021	7.48692
2022	6.81318