Year	Cases per 100,000
1990	12.2
1991	13.6
1992	14.5
1993	15.4
1994	16.4
1995	17.6
1996	19.1
1997	21.3
1998	23.9
1999	26.6
2000	29.1
2001	31.2
2002	32.7
2003	33.2
2004	32.5
2005	31
2006	29.2
2007	27.7