Year	Percent
1990	87.1
1991	86.1
1992	85.1
1993	86.4
1994	86.6
1995	87.3
1996	86.9
1997	86.9
1998	87
1999	87
2000	86.1
2002	86
2003	86.2
2004	86.2
2005	86.25
2006	85.5
2007	85.7
2008	85.8
2009	85.8