Year	Percent
1992	85.8
1993	86.9
1994	88
1995	88.3
1996	89.9
1997	89.5
1998	90
1999	90.1
2000	90.5
2001	92.1
2002	94.2
2003	92.5
2004	91.3
2005	91.1
2006	91
2007	91.5
2008	91.8
2009	94.2
2010	92.7
2011	93.5
2012	94.3
2013	91.4
2014	93.9
2015	95
2016	94.6