Year	Cases per 100,000
1990	0
1991	0
1992	0
1993	0
1994	0.1
1995	0.1
1996	0.2
1997	0.4
1998	0.6
1999	0.9
2000	1.3
2001	1.5
2002	1.7
2003	1.9
2004	1.9
2005	2
2006	2.1
2007	2.1