Dust-to-gas ratio as a function of R/R₂₅ for non-deficient (red circles), def_HI < 0.4, slightly HI-deficient 0.4 ≤  def_HI ≤  0.7, and HI-deficient galaxies (blue stars), def_HI > 0.7. The solid line shows the profile for the new mapped galaxies. The black solid line shows the average profiles. The molecular content has been estimated using both the Galactic X_CO (top row) and the X_CO of Eq. (1) (bottom row).