Year	Cases per 100,000
1990	10
1991	11
1992	11.7
1993	12.4
1994	13
1995	13.8
1996	14.5
1997	15.5
1998	16.7
1999	18.2
2000	19.8
2001	21.5
2002	23
2003	24
2004	24.3
2005	24.1
2006	23.5
2007	23