Year	Cases per 100,000
1990	0.2
1991	0.3
1992	0.5
1993	0.7
1994	0.9
1995	1.2
1996	1.5
1997	1.7
1998	1.9
1999	2
2000	2.1
2001	2.1
2002	2.1
2003	2.1
2004	2.1
2005	2.1
2006	2.1
2007	2.1