Year	Cases per 100,000
1990	1.3
1991	1.6
1992	2.1
1993	2.8
1994	3.7
1995	4.9
1996	6.3
1997	7.9
1998	9.5
1999	11
2000	12.2
2001	13.2
2002	14
2003	14.7
2004	15.2
2005	15.7
2006	16
2007	16.3