Year	Percent
1990	93.7
1991	94.2
1992	94.6
1993	94.9
1994	94.4
1995	94.8
1996	95
1997	95
1998	96.5
1999	96.6
2000	96.7
2001	96.7
2002	96.8
2003	96.4
2004	97.2
2005	97.42
2006	97.66
2007	97.75
2008	97.82
2009	97.82