Year	Percent
1991	47.3
1992	51.9
1993	54.4
1994	54.9
1995	55.4
1996	54.7
1997	56.5
1998	57
1999	46.67
2000	47.46
2001	47.74
2002	47.4
2004	48.62
2005	46.99
2006	47.72
2007	48.24
2008	49.54