Year	Cases per 100,000
1990	0.5
1991	0.6
1992	0.8
1993	0.9
1994	1
1995	1.2
1996	1.4
1997	1.6
1998	1.7
1999	1.9
2000	2.2
2001	2.3
2002	2.5
2003	2.7
2004	2.9
2005	3.1
2006	3.2
2007	3.3