Year	Cases per 100,000
1980	22
1981	23
1982	15
1983	21
1984	20
1985	13
1986	15
1987	20
1988	19
1989	18
1990	20
1991	12
1992	14
1993	11
1994	13
1996	13
1997	18
1998	20
1999	22
2000	20
2001	17
2002	22
2003	21
2004	22
2005	26
2006	28