Year	Cases per 100,000
1980	19
1981	20
1982	19
1983	19
1984	20
1985	20
1986	35
1987	37
1988	41
1989	44
1990	47
1991	43
1992	40
1994	36
1995	30
1996	35
1997	32
1998	34
1999	34
2000	31
2001	29
2002	27
2003	27
2004	25
2005	23
2006	20
2007	21