Year	Percent
1990	93.47
1991	93.45
1992	93.4
1993	93.4
1994	93.36
1995	93.32
1996	93.31
1997	93.32
1998	93.3
1999	93.3
2000	93.41
2001	93.48
2002	93.52
2003	93.51
2004	93.5
2005	93.5
2006	93.48
2007	93.46
2008	93.45
2009	93.52
2010	93.52
2011	93.48
2012	93.49
2013	93.51
2014	93.54
2015	93.55
2016	93.56
2017	93.55
2018	93.55
2019	93.54