Year	Percent
1995	30.78
1996	29.12
1997	30.42
1998	34.33
1999	33.98
2000	36.01
2001	36.77
2002	35.38
2003	37.08
2004	37.74
2005	39.51
2006	39.74
2007	40.58
2008	39.65
2009	39.68
2010	39.68