Year	Percent
1989	99.7
1990	99.7
1991	99.7
1992	98.3
1993	95.5
1994	93.3
1995	93.1
1996	95.7
1997	96.4
1998	97.4
1999	98.8
2000	96.8
2001	98.4
2002	98.8
2003	99.2
2004	99.5
2005	97.8
2006	99.7
2007	99.9
2008	99.9
2009	100
2010	99.5
2011	100
2012	100
2013	100
2014	100
2016	99.8