Year	Percent
1990	15
1991	15
1992	15
1993	15
1994	15
1995	15.5
1996	15.3
1997	15.3
1998	14
1999	13.3
2000	12
2001	12
2002	12
2003	12.9
2004	19.14
2005	11.05
2006	11.63
2007	13.67