Dipole frequencies of all RGB stars used in the present analysis normalised by the median dipole frequency of the star. Modes with azimuthal orders − 1, 0, 1 are shown (with a slight offset to one another) in red, black, and orange, respectively. Star names with a superscript “a” or “b” indicate that the data are taken from Datta et al. (2015) or Di Mauro et al. (2016), respectively. All other data are taken from Corsaro et al. (2015). On the left the period spacings presented in these references are shown (including the updates by Corsaro; see text). The stars are ordered following the RGB with the least-evolved star at the bottom and the most-evolved star at the top.