Year	Percent
1995	13.28
1996	13.4
1997	13.91
1998	14.24
1999	14.59
2000	15.14
2001	15.53
2002	16.19
2003	16.66
2004	17.2
2005	17.58
2006	17.63
2007	17.91
2008	18.05
2009	18.14
2010	18.06