Year	Cases per 100,000
1990	0.9
1991	2.4
1992	5.7
1993	11.8
1994	20
1995	27.6
1996	32.8
1997	35.4
1998	36.4
1999	36.5
2000	36.2
2001	35.6
2002	34.9
2003	34.2
2004	33.5
2005	32.8
2006	32.1
2007	31.6