Year	Cases per 100,000
1980	20
1981	12
1982	11
1983	11
1984	13
1985	11
1986	12
1987	13
1988	4
1989	12
1990	13
1991	12
1992	6
1993	9
1994	8
1995	8
1996	10
1997	9
1998	10
1999	9
2000	10
2001	7
2002	7
2003	12
2004	7
2005	8
2006	7
2007	8