Year	Cases per 100,000
1980	46
1981	47
1982	35
1983	31
1984	20
1985	20
1986	17
1987	18
1988	19
1989	19
1990	17
1991	18
1992	17
1993	17
1994	18
1995	12
1996	22
1997	25
1998	22
1999	20
2000	18
2001	19
2002	17
2003	17
2004	15
2005	18
2006	17
2007	17