Various experiments on the charge state dependence of secondary ion emission from insulators have been performed recently using the heavy ion accelerators in Orsay and Darmstadt. A survey of the results is presented with the intention of exhibiting phenomenological trends over a wide range of beam parameters. The yields of certain small fragment ions ejected from organic samples depend strongly on the initial charge of the incident ions but not on their atomic number. Large molecule-specific ions show a different behaviour. Their yields increase considerably with the atomic number when the initial charge state is kept constant. This phenomenon is interpreted in terms of a depth contribution to desorption. By means of an averaging procedure, we calculated a mean interaction depth, from which contributions to desorption reach the surface. For a coronen target, this mean interaction depth ranges from 12 to 160 Å, when the target is irradiated by 1.16 MeV/n beams of Ne, Ar, and Kr having charge states from 5+ to 24+. The interaction depth, as defined in this work, increases linearly with the specific energy loss. An attempt was made to introduce the depth effect into the ion track model. The range of interaction predicted by these model calculations can not, however, reproduce the experimental observations.