Year	Cases per 100,000
1990	0.3
1991	0.4
1992	0.6
1993	0.8
1994	1
1995	1.2
1996	1.4
1997	1.5
1998	1.6
1999	1.7
2000	1.8
2001	1.8
2002	1.9
2003	1.9
2004	1.9
2005	1.9
2006	1.9
2007	2