KDE of the excess CN-index δS(3839) for NGC 3201 in comparison with two normal Galactic GCs (NGC 288, NGC 362) and one anomalous (M 22), as indicated in the panels. Data for the reference clusters were taken from Kayser et al. (2008) and put in a standard scale. The rug plot indicates the positions of all stars in each panel. The KDE bandwidth is the average uncertainty of each dataset, i.e., σ_NGC288 = 0.055, σ_NGC362 = 0.042, σ_M22 = 0.046, σ_NGC3201 = 0.031. Multi-Gaussian fitting was performed to each distribution, except pec and S2 stars, as discussed in the text. We also indicate cluster metallicities in the scale of Dias et al. (2016a).