Year	Percent
1995	15.99
1996	25.6
1997	23.73
1998	18.15
1999	18.19
2000	20.44
2001	23.5
2002	26.29
2003	28.08
2004	28.69
2005	20.53
2006	25.04
2007	32.32
2008	32.58
2009	36.64
2010	37.23