Year	Cases per 100,000
1990	3.7
1991	5.3
1992	7
1993	9.2
1994	11.8
1995	14.7
1996	17.6
1997	21
1998	24.7
1999	28.6
2000	32.8
2001	36.8
2002	40.3
2003	42.7
2004	43.5
2005	43.1
2006	42.1
2007	41