Year	Cases per 100,000
1990	0
1991	0.1
1992	0.1
1993	0.2
1994	0.4
1995	0.9
1996	1.7
1997	3.2
1998	5.3
1999	7.8
2000	10.2
2001	12.2
2002	13.6
2003	14.6
2004	15.3
2005	16
2006	16.5
2007	17