Year	Percent
1996	17.7
1997	17.82
1998	17.36
1999	17.15
2000	14.96
2001	15.39
2002	15.06
2003	14.05
2004	13.92
2005	14.14
2006	13.98
2007	13.51
2008	13.35
2013	11.65