Year	%
1971	96.86313
1972	97.78332
1973	98.20958
1974	98.19556
1975	99.26621
1976	99.30773
1977	98.01433
1978	99.04065
1980	95.4575
1982	98.65429
1983	97.91044
1984	92.39789
1985	88.19036
1986	89.39526
1987	88.18898
1988	98.79804
1989	94.04162
1990	96.13354
1991	99.93502
1992	99.03849
1993	94.72991
1994	99.96362
1995	99.00544
1996	99.97973
1997	98.04887
1998	99.79889
1999	97.97195
2000	98.46756
2001	98.71409
2002	99.66991
2004	99.28263
2005	93.89873
2006	97.57981
2007	99.79025
2010	97.49609
2011	99.39555
2012	98.95627
2013	97.79729
2014	96.78849
2015	98.58775
2016	98.89143