Year	Percent
1995	13.35
1996	13.07
1997	14.18
1998	14.21
1999	14.27
2000	15.11
2001	18.86
2002	18.58
2003	17.99
2004	18.63
2005	18.84
2006	18.87
2007	18.64
2008	18.5
2009	18.51
2010	18.9