Year	Cases per 100,000
1990	0.3
1991	0.4
1992	0.5
1993	0.6
1994	0.7
1995	0.9
1996	1.1
1997	1.3
1998	1.5
1999	1.8
2000	2
2001	2.3
2002	2.6
2003	2.9
2004	3.1
2005	3.4
2006	3.6
2007	3.8