Upper panel: distribution of galaxies in our sample vs. their Hubble type. The black and orange dotted lines correspond to the histogram of all the S⁴G galaxies and those with inclination lower than 65°, respectively. For the galaxies with i< 65°, we display the histogram of barred galaxies in the Hubble sequence (solid lines), according to the various criteria explained in the text. Lower panel: bar fraction vs. Hubble stage for a sample of face-on and moderately inclined galaxies (i< 65°). The fraction of galaxies with an identifiable maximum in the amplitude of their higher order even Fourier components is also shown. Uncertainties are calculated assuming a binomial distribution.