Year	Cases per 100,000
1990	4.4
1991	6.4
1992	8.5
1993	11.2
1994	14.1
1995	17.3
1996	20.4
1997	23.7
1998	27.2
1999	30.9
2000	34.8
2001	38.4
2002	41.6
2003	43.8
2004	44.4
2005	43.9
2006	42.8
2007	41.6