Year	Percent
1987	0.1952
1988	4.687
1989	3.586
1990	4.361
1991	6.45
1992	6.551
1993	6.605
1994	6.664
1995	0.5196
1996	0.3684
1997	0.2764
1998	0.3824
1999	1.097
2000	2.961
2001	2.04
2002	4.069
2003	3.243
2004	3.346
2005	3.044
2006	3.237
2007	3.428