Year	Cases per 100,000
1990	34.6
1991	54.7
1992	80.4
1993	113.7
1994	152.4
1995	195
1996	236.3
1997	280.5
1998	324.6
1999	369.7
2000	416.7
2001	461.4
2002	501
2003	528.3
2004	538.2
2005	535.2
2006	524.5
2007	515.6