Year	Percent
1995	15.12
1996	15.53
1997	15.81
1998	16.66
1999	17.05
2000	16.84
2001	16.99
2002	17.94
2003	17.22
2004	17.39
2005	17.23
2006	16.96
2007	17.31
2008	17.07
2009	16.26
2010	15.89
2011	15.81