Year	Percent
1995	53.56
1996	54.47
1997	54.95
1998	54.66
1999	55.14
2000	55.43
2001	56.93
2002	57.74
2003	58.35
2004	58.39
2005	59.46
2006	59.12
2007	59.27
2008	59.5
2009	59.72
2010	59.02