Year	Cases per 100,000
1980	27
1981	29
1982	27
1983	22
1984	22
1985	20
1986	19
1987	18
1988	16
1989	17
1990	16
1991	15
1992	13
1993	15
1994	15
1995	14
1996	13
1997	12
1998	12
1999	11
2000	13
2001	13
2002	12
2003	10
2004	11
2005	10
2006	10
2007	9