Year	% of total
1960	100
1961	100
1962	100
1963	100
1964	100
1965	100
1966	100
1967	100
1968	100
1969	100
1970	100
1971	100
1972	100
1973	100
1974	100
1975	100
1976	100
1977	100
1978	100
1979	100
1980	100
1981	100
1982	100
1983	100
1984	100
1985	100
1986	100
1987	100
1988	100
1989	100
1990	96.64720338983051
1991	97.57408695652174
1992	97.10759259259258
1993	96.21669724770642
1994	98.3068085106383
1995	95.62960784313725
1996	96.0846835443038
1997	92.52779069767442
1998	94.71337142857142
1999	96.52218390804597
2000	96.97668674698797
2001	97.26493902439024
2002	97.56030864197531
2003	96.65487654320988
2004	97.49389221556885
2005	97.12594594594594
2006	97.05142857142857
2007	97.633875
2008	97.4046875
2009	96.65487654320988
2010	97.71721590909091
2011	97.38590163934427
2012	99.7424
2013	97.78666666666666
2014	97.54932038834951
2015	95.87863414634145
2016	94.6117748917749