Year	Cases per 100,000
1980	32
1981	30
1982	28
1983	25
1984	22
1985	20
1986	19
1987	18
1988	16
1989	16
1990	16
1991	15
1992	15
1993	17
1994	16
1995	15
1996	13
1997	12
1998	10
1999	10
2000	10
2001	10
2002	10
2003	10
2004	8
2005	8
2006	8
2007	9