Year	Cases per 100,000
1990	9.4
1991	13.2
1992	15.4
1993	16.5
1994	17.1
1995	17.6
1996	18.1
1997	18.7
1998	19.4
1999	20.2
2000	21
2001	21.8
2002	22.6
2003	23.3
2004	24
2005	24.6
2006	25.2
2007	25.7