Year	Percent
1992	86.36
1993	79.19
1994	77.65
1995	76.53
1996	75.31
1997	75
1998	71.54
1999	71.34
2000	72.55
2001	71.72
2002	71.38
2003	72.08
2004	66.93
2005	70.69
2006	75.81
2007	76.74
2008	80.08
2009	79.72
2010	78.53