Year	Cases per 100,000
1980	18
1981	19
1982	18
1983	17
1984	15
1985	15
1986	13
1987	15
1988	18
1989	16
1990	19
1991	16
1992	14
1993	13
1994	13
1995	12
1996	11
1997	10
1998	10
1999	10
2000	7
2001	7
2002	8
2003	8
2004	7
2005	7
2006	6
2007	6