Year	Cases per 100,000
1990	4.06
1991	4.06
1992	4.06
1993	4.07
1994	4.07
1995	4.08
1996	4.06
1997	4.04
1998	4
1999	3.9
2000	3.82
2001	3.79
2002	3.78
2003	3.78
2004	3.78
2005	3.79
2006	3.8
2007	3.74
2008	3.69
2009	3.64
2010	3.61
2011	3.56
2012	3.53
2013	3.47
2014	3.42
2015	3.44
2016	3.44