Fraction of galaxies with O32 > 1 in bins of 1 dex with central log M_∗M_⊙ = 7.5, 8.5, and 9.5 of our MUSE sample (black/grey) and the SDSS comparison sample (red; see the text for details). The points denote the centres of the stellar mass bins and their size reflects the number of galaxies in the bin. The shaded areas cover the 1-σ errors as calculated by bootstrapping in the y-direction and the bin size in the x-direction.