Year	% of total
1971	90.47619047619048
1972	90.40404040404042
1973	90.47619047619048
1974	89.78260869565217
1975	82.08
1976	89.51310861423221
1977	82.59149357072205
1978	88.65826538176427
1979	94.46401610468043
1980	97.30960264900662
1981	97.93253536452666
1982	98.00588427590716
1983	98.70210135970335
1984	98.42829076620825
1985	99.21499113699672
1986	99.11359925355725
1987	99.12983741699108
1988	100
1989	100
1990	100
1991	100
1992	100
1993	100
1994	100
1995	100
1996	100
1997	100
1998	100
1999	100
2000	100
2001	100
2002	100
2003	100
2004	100
2005	100
2006	100
2007	100
2008	100
2009	100
2010	100
2011	100
2012	100
2013	100
2014	100
2015	100