Year	Cases per 100,000
1990	0.1
1991	0.1
1992	0.2
1993	0.3
1994	0.4
1995	0.6
1996	1
1997	1.4
1998	2.1
1999	2.8
2000	3.7
2001	4.5
2002	5.2
2003	5.8
2004	6.3
2005	6.6
2006	6.8
2007	6.9