Year	Cases per 100,000
1980	29
1981	27
1982	26
1983	24
1984	23
1985	19
1986	18
1987	18
1988	18
1989	17
1990	20
1991	18
1992	17
1993	16
1994	16
1995	18
1996	16
1997	17
1998	16
1999	13
2000	15
2001	12
2002	13
2003	12
2004	11
2005	11
2006	10
2007	10