Year	Cases per 100,000
1990	0
1991	0
1992	0
1993	0
1994	0
1995	0
1996	0.1
1997	0.1
1998	0.2
1999	0.3
2000	0.4
2001	0.7
2002	1.1
2003	1.5
2004	2.1
2005	2.8
2006	3.6
2007	4.6