Ratio ${r_X}$ of the charged-particle pseudorapidity density in Pb\==Pb (top) and p\==Pb (bottom) in different centrality classes to the charged-particle pseudorapidity density in pp in the \INELGtZero{} event class. Note, for Pb\==Pb ${\etalab}$ is the same as the centre-of-mass pseudorapidity.