Year	Percent
1990	69.2
1991	70.1
1992	71.1
1993	72.1
1994	73
1995	73.6
1996	74.3
1997	74.9
1998	76
1999	76.1
2000	76.6
2001	77.1
2002	77.7
2003	78.22
2005	79
2006	79.29
2007	79.6
2008	79.86
2009	80.11