Year	Cases per 100,000
1990	0.5
1991	0.8
1992	1
1993	1.4
1994	1.8
1995	2.1
1996	2.5
1997	2.7
1998	2.9
1999	3
2000	3
2001	3
2002	3
2003	2.9
2004	2.8
2005	2.8
2006	2.7
2007	2.6