Upper panel: histograms of the distributions of the galaxies in our sample (showing the barred galaxies separately) and of the different arm classes (grand-design, multi-armed, and flocculent) as a function of revised Hubble stage. Small offsets (≤0.1) have been added in the x-axis for the sake of avoiding line overlapping. Lower panel: bar fraction for the different spiral types. With vertical lines we represent binomial counting errors.