Year	%
1971	98.82812
1972	100
1973	100
1974	100
1975	100
1976	100
1977	100
1978	99.03632
1979	99.25424
1980	100
1981	100
1983	100
1984	99.29117
1985	99.19759
1986	98.93563
1987	100
1988	100
1989	98.26712
1990	100
1991	93.45441
1992	99.74208
1993	100
1994	99.73392
1995	100
2004	100
2005	100
2006	100
2007	99.78205
2008	99.19813
2010	100
2012	100
2013	99.52277
2014	98.99711
2015	99.10936
2016	98.66245