Year	Cases per 100,000
1990	2.3
1991	4.2
1992	7
1993	10.4
1994	13.6
1995	16.3
1996	18.5
1997	20.5
1998	22.6
1999	25.2
2000	28.2
2001	31.9
2002	36.1
2003	40.4
2004	44.8
2005	49
2006	53.1
2007	57.1