Year	%
1991	98.62903
1992	99.20563
1993	99.00666
1994	98.05036
1995	99.17708
1996	99.35825
1997	98.27164
1998	99.37904
1999	99.33983
2000	99.46915
2001	99.32281
2002	99.36369
2003	99.45272
2004	99.38136
2005	99.24138
2006	98.89633
2007	98.88058
2008	98.91816
2009	98.78455
2010	98.94015
2011	98.93983
2012	98.6015
2013	98.85251
2014	99.04631
2015	99.23571
2016	99.33394
2017	99.3358