Year	Cases per 100,000
1980	66
1981	51
1982	47
1983	53
1984	58
1985	53
1986	38
1987	26
1988	15
1989	38
1990	24
1991	21
1992	30
1993	34
1994	24
1995	21
1996	23
1997	21
1998	31
1999	22
2000	24
2001	12
2002	29
2003	16
2004	12
2005	18
2006	18
2007	23