Year	Percent
1995	16.09
1996	16.95
1997	16.87
1998	19.9
1999	18.61
2000	19.8
2001	19.25
2002	18.82
2003	18.26
2004	18.26
2005	18.62
2006	18.66
2007	18.04
2008	18.19
2009	19.54
2010	20.52