Year	Percent
1965	23.44504
1966	21.00165
1967	21.73716
1968	22.42223
1969	19.33005
1970	19.93906
1971	21.86719
1972	21.25509
1973	20.82618
1974	20.65593
1975	17.89844
1976	19.25347
1977	16.38432
1978	18.91975
1979	17.91661
1980	15.12214
1981	10.68485
1982	12.91555
1983	12.62338
1984	12.12317
1985	13.29093
1986	15.70511
1987	11.76452
1988	14.20342
1989	14.3519
1990	15.09518
1991	17.49944
1992	14.04276
1993	13.06941
1994	17.25951
1995	13.49265
1996	18.43998
1997	14.63418
1998	14.48679
1999	12.47664
2000	10.72863
2001	11.87618
2002	11.84328
2003	12.49186
2004	11.86933
2005	10.69888
2006	12.30417
2007	9.87525
2008	10.86496
2009	11.96505
2010	11.96208
2011	12.0819
2012	11.32975
2013	12.35837
2014	10.35315
2015	11.79619
2016	10.32197
2017	11.16029
2018	11.30554
2019	10.8424
2020	10.66364
2021	11.99559
2022	10.33155