Year	Cases per 100,000
1990	0.9
1991	1.3
1992	1.9
1993	2.8
1994	4
1995	5.5
1996	7.2
1997	9
1998	10.8
1999	12.4
2000	13.7
2001	14.7
2002	15.5
2003	16.1
2004	16.5
2005	16.7
2006	16.9
2007	17