Year	%
1980	98.40156
1981	98.47977
1982	98.70546
1983	99.34169
1984	98.89938
1985	99.60102
1986	99.72062
1987	97.81463
1988	98.67435
1989	99.49485
1992	99.54158
1993	98.89136
2008	100
2009	99.00575
2013	99.97917
2014	100
2015	99.31164
2016	100