Fig. 2

Odds of seizures per year and by detected substance; Chi-square test for homogeneity of odds. Cannabis resin: the odds in 2008 were higher than in all other years, except 2009, 2012 and 2016; the lowest values were in 2014 and 2017; the odds in 2013 were lower compared to 2009, 2012, 2015 and 2016 (P < 0.05); Cannabis herb: minimum values were in 2008 and 2009; the odds in the three-year period 2010–2012 were lower than in all years from 2013 onwards, except 2012 vs. 2015; the maximum values were in 2013, 2014 and 2017; the odds in 2016 were higher than in 2012 and 2015 (P < 0.05); Cocaine: the odds in 2008 were higher than in 2012–2017; in 2009 were higher than in 2013–2017, except 2015; the odds in 2010–2011 and in 2014 were higher compared to 2016; the odds in 2013 were lower than in 2008–2011 and 2015; the odds in 2016 were lower than in other years (P < 0.05), except 2013 and 2017; Heroin: the odds in 2008 were higher compared to those in the years 2013 and 2015–2017; in 2009 were higher than 2008 and 2012–2017; the values in 2010–2011 were higher than in 2012–2017, except 2014; the odds in 2013, 2015 and 2016 were lower compared to 2008–2011 and 2014; the odds in 2017 were lower than in all other years (P < 0.05), except 2013 e 2016