Year	Cases per 100,000
1980	28
1981	26
1982	26
1983	26
1984	28
1985	28
1986	28
1987	27
1988	24
1989	24
1990	28
1991	26
1992	26
1993	24
1994	23
1995	25
1996	25
1997	26
1998	27
1999	28
2000	26
2001	25
2002	24
2003	26
2004	26
2005	26
2006	25
2007	23