Year	Cases per 100,000
1990	2.3
1991	2.7
1992	3.1
1993	3.5
1994	3.8
1995	4.1
1996	4.3
1997	4.4
1998	4.4
1999	4.3
2000	4.1
2001	4.1
2002	4
2003	3.8
2004	3.5
2005	3.3
2006	3.1
2007	2.9