Year	Percent
1995	27.98
1996	29.76
1997	28.79
1998	29.06
1999	28.6
2000	29.05
2001	29.32
2002	29.81
2003	30.74
2004	30.57
2005	29.44
2006	28.38
2007	25
2008	22.18
2009	19.88
2010	29.88