Year	Percent
1990	13.4
1991	13.6
1992	14
1993	14.2
1995	12.7
1996	13.3
1997	18.9
1998	18.9
1999	18.9
2000	18.9
2001	16.87
2002	16.87
2003	14.94
2004	14.97
2006	14.82
2007	14.82