Year	Cases per 100,000
1990	1.3
1991	1.7
1992	2
1993	2.2
1994	2.5
1995	2.6
1996	2.8
1997	2.9
1998	2.9
1999	3
2000	3.1
2001	3.1
2002	3.1
2003	3.1
2004	3.2
2005	3.2
2006	3.2
2007	3.3