Year	Cases per 100,000
1980	38
1981	32
1982	28
1983	26
1984	24
1985	27
1986	41
1987	18
1988	18
1989	23
1990	27
1991	27
1992	16
1993	30
1994	27
1995	27
1996	18
1997	19
1998	13
1999	18
2000	24
2001	12
2002	17
2003	15
2004	19
2005	13
2006	13