Year	Cases per 100,000
1980	21
1981	16
1982	14
1983	14
1984	12
1985	10
1986	11
1987	9
1988	8
1989	9
1990	5
1991	7
1993	7
1994	7
1995	7
1996	6
1997	7
1998	5
1999	5
2000	5
2001	3
2002	3
2003	3
2004	3
2005	3
2006	3
2007	2