Year	Percent
1995	17.01
1996	19.28
1997	18.87
1998	19.7
1999	19.21
2000	22.39
2001	17.35
2002	18.82
2003	17.91
2004	18.37
2005	18.29
2006	17.16
2007	19.31
2008	19.69
2009	13.19
2010	17.78