Year	Cases per 100,000
1990	30
1991	28
1992	27
1993	25
1994	24
1995	23
1996	19
1997	18
1998	17
1999	19
2000	19
2001	18
2002	18
2003	17
2004	17
2005	16
2006	16
2007	16
