Year	Percent
1964	43.46261
1965	50.21583
1966	25.56756
1967	14.76432
1968	22.3758
1969	19.75436
1970	14.66048
1971	15.71758
1972	15.28
1973	14.66483
1974	15.24058
1975	21.1115
1976	21.97915
1977	15.07762
1978	15.54548
1979	30.81378
1980	22.17272
1981	28.53368
1982	34.46762
1983	31.65884
1984	33.29807
1985	27.46114
1986	28.10988
1987	28.78103
1988	39.12923
1989	51.45787
1990	57.02768
1991	53.61268
1992	63.70675
1993	90.39557
1994	49.15273
1995	37.13944
1996	32.99102
1997	22.59227
1998	17.65058
1999	15.54972
2000	23.2278
2001	19.36015
2002	19.50528
2003	21.28565
2004	24.02524
2005	22.87659
2006	19.5679
2007	20.33382
2008	19.36644
2009	22.13136
2010	16.89541
2011	24.1653
2012	21.20159
2013	23.93232
2014	15.61839
2015	15.89496
2016	15.11783
2017	14.63118
2018	13.94334
2019	16.33744
2020	20.17082
2021	14.04966