SED-derived DTM ratio, DTM_SED = log A_V − (log N_HI + [M/H]_tot) (top), and depletion-derived DTM_mass ratio (bottom) as a function of redshift. Red dots (measurements) and triangles (1σ upper limits) denote the GRB host-galaxy absorbers. Gray symbols show the equivalent values for the MW, LMC, and SMC. The Pearson correlation coefficients, r, are marked for each data set. We observe no clear evolution of DTM_SED with redshift but do see a mild evolution of DTM_mass; the best-fit relation is shown as the solid black line, and the dark- and light-shaded gray regions indicate the 1 and 2σ confidence intervals.