This includes everyone in the 12–15, 16–19, and more than 19 class intervals. Pictograms use pictures to represent data. To make sense, a pictogram must always have a key. In a pictogram it is ...

Correspondence to Dr Nadja Mallock, Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), 10589 Berlin, Germany; nadja.mallock{at}bfr.bund.de Background ...