Year	Cases per 100,000
1968	19.34
1969	16.93
1970	17.89
1971	15.4895
1972	16.019
1973	14.2485
1974	16.078
1975	14.2375
1976	15.027
1977	15.6565
1978	16.416
1979	17.7155
1980	16.655
1981	17.6245
1982	16.854
1983	17.4535
1984	19.833
1985	18.2625
1986	18.732
1987	21.1715
1988	21.031
1989	18.8105
1990	19.87
1991	19.93
1992	19.6
1993	19.48
1994	19.07
1995	18.87
1996	18.4
1997	18.47
1998	18.26
1999	18.08
2000	17.65
2001	17.65
2002	17.43
2003	17.47
2004	17.51
2005	17.76
2006	17.78
2007	18.19
2008	17.81
2009	17.91
2010	17.55
2011	17.47
2012	17.27
2013	17.15
2014	16.83
2015	16.58
2016	16.39