Year	Percent
1991	6.812
1992	5.299
1993	9.408
1994	12.4
1995	10.58
1996	12.51
1997	16.7
1998	15.75
1999	21.29
2000	33.29
2001	18.2
2002	17.18
2003	15.44
2004	11.43
2005	19.13
2006	15.65
2007	14.07