Year	% of total
1971	98.4
1972	98.4
1973	100
1974	98.4
1975	98.4
1976	98.4
1977	98.4
1978	98.4
1979	98.4
1980	98.83381924198251
1981	99.15433403805497
1982	99.29453262786596
1983	99.41348973607037
1984	99.46666666666667
1985	99.47780678851174
1986	99.09909909909909
1987	99.32821497120922
1988	99.36131386861314
1989	99.02826855123675
1990	99.06143344709898
1991	99.05437352245863
1992	99.14712153518124
1993	99.09560723514211
1994	99.15814792543596
1995	99.23702950152594
1996	99.24634950541686
1997	99.21063564603242
1998	99.12140575079871
1999	99.0961380443714
2000	99.09555642941407
2001	99.06940674680108
2002	99.07441688263606
2003	99.2165465371357
2004	99.11151960784314
2005	99.11151960784314
2006	99.0600363856883
2007	99.0279823269514
2008	99.03593339176162
2009	98.97563676633445
2010	98.99789029535864
2011	98.95302013422818
2012	99.00763358778626
2013	99.04588823262154
2014	99.00133155792277
2015	98.95238095238095