Dust mass fraction inferred for all individual QGs in our sample for different redshift bins. All QGs are individually undetected; therefore, triangles show the inferred 3 σ upper limits. The two high-weight galaxies are indicated by the large solid triangles and have redshifts of z ∼ 0.6 and z ∼ 1.1, respectively. Circles show the upper limits of the stacks in each bin as shown in Fig. 4 (i.e. without the high-weight sources). The coloured contours represent the number density distribution within each redshift bin.