Year	Cases per 100,000
1990	0.6
1991	0.9
1992	1.2
1993	1.7
1994	2.3
1995	3.1
1996	4.1
1997	5.4
1998	6.8
1999	8.3
2000	9.8
2001	11.3
2002	12.6
2003	13.7
2004	14.6
2005	15.2
2006	16
2007	16.7