Year	Percent
1992	60.1
1994	42.03
1995	47.83
1996	41.05
1997	36.01
1998	18.41
1999	14.65
2000	18.76
2001	22.67
2002	22.16
2003	39.23
2004	39.96
2005	35.7
2006	35.41
2007	28.17