Year	Cases per 100,000
1980	26
1981	1
1982	12
1983	7
1984	6
1985	5
1986	3
1987	1
1988	2
1989	2
1990	2
1991	2
1992	2
1995	1
1996	1
1997	2
1998	2
1999	1
2000	1
2001	2
2002	2
2004	7
2006	2
2007	5