Year	Cases per 100,000
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0.1
1997	0.1
1998	0.3
1999	0.6
2000	1
2001	1.7
2002	2.4
2003	2.8
2004	3
2005	3
2006	2.9
2007	2.7