Year	Cases per 100,000
1968	29.08
1969	25.1
1970	25.09
1971	22.1885
1972	21.897
1973	20.8055
1974	19.834
1975	19.7225
1976	19.221
1977	19.3395
1978	16.888
1979	16.3365
1980	15.875
1981	14.7835
1982	15.892
1983	15.6305
1984	15.499
1985	13.9475
1986	14.756
1987	14.2745
1988	14.203
1989	13.8215
1990	14.94
1991	14.47
1992	13.89
1993	13.61
1994	13.34
1995	13.2
1996	12.58
1997	12.38
1998	11.98
1999	11.64
2000	11.27
2001	11.05
2002	10.74
2003	10.62
2004	10.56
2005	10.53
2006	10.44
2007	10.54
2008	10.47
2009	10.64
2010	10.44
2011	10.53
2012	10.5
2013	10.44
2014	10.33
2015	10.37
2016	10.44