Year	Cases per 100,000
1980	15
1981	22
1982	29
1983	91
1984	22
1985	15
1986	14
1987	24
1988	16
1989	17
1990	31
1991	47
1992	33
1993	40
1994	28
1995	44
1996	45
1997	47
1998	53
1999	44
2000	43
2001	54
2002	53
2003	38
2004	31
2005	37
2006	30
2007	22