Year	Percent
1990	55.1
1991	68.7
1992	70.6
1993	70.4
1994	73.5
1995	76.3
1996	80.5
1997	82.8
1998	86.5
2003	93.97
2004	93.43
2005	91.16
2006	91.43
2007	90.26
2008	89.88
2009	88.49