Year	Percent
1990	21.19
1991	25.36
1992	24.9
1993	24.99
1994	24.49
1995	26.7
1996	28.57
1997	27.78
1998	27.75
1999	28.23
2000	27.76
2001	27.6
2002	28.04
2003	28.18
2004	27.49
2005	27.59
2006	26.26
2007	24.06
2008	24.58
2009	26.17
2010	22.86