Year	Cases per 100,000
1980	7
1981	7
1982	6
1983	10
1984	9
1985	10
1986	10
1987	10
1988	9
1989	10
1990	10
1991	11
1992	11
1993	9
1994	10
1995	13
1996	16
1997	20
1998	15
1999	12
2000	15
2001	16
2002	10
2003	11
2004	13
2005	13
2006	17
2007	16