Year	Cases per 100,000
1990	0.6
1991	0.8
1992	1.1
1993	1.4
1994	1.9
1995	2.5
1996	3.2
1997	4
1998	4.8
1999	5.5
2000	6.1
2001	6.6
2002	7
2003	7.3
2004	7.6
2005	7.8
2006	8
2007	8.2