B.R.$_{\psi(\rm 2S)\rightarrow\mu^{+}\mu^{-}}{\sigma_{\psi(\rm 2S)}}$/B.R.$_{J/\psi\rightarrow\mu^{+}\mu^{-}}{\sigma_{\rm J/\psi}}$ as a function of $\langle N_{\rm coll} \rangle$ at backward (left) and forward (right) rapidity compared with the measurement in pp collisions at $\sqrt{s} = 7$ TeV  (line with the band representing the total uncertainty), and to the results at $\sqrt{s_{\rm NN}} = 5.02$ TeV . Vertical error bars represent the statistical uncertainties, while the open boxes correspond to the systematic uncertainties.