Year	Percent
1992	29.1
1993	29.25
1994	29.39
1995	29.53
1996	29.68
1997	29.82
1998	29.97
1999	30.11
2000	30.25
2001	30.29
2002	30.32
2003	30.35
2004	30.38
2005	30.41