Observed abundances of Zn, with respect to H and Fe. The trend (dashed curve, [Zn/Fe] = 0.73 × [Zn/H] + 1.26 with an intrinsic scatter of 0.3 dex and a Pearson correlation coefficient of 0.81, from a linear fit to the DLA, black squares, and Galactic data, orange diamonds) is due to dust depletion, because Fe is more heavily depleted than Zn. This relation is used here only to allow a more reasonable assumption on the nucleosynthesis, i.e. to convert the literature information on nucleosynthesis – often expressed as a function of metallicity – to a scale of [Zn/Fe].