Values of $\frac{2}{\langle N_{\rm part} \rangle} \langle N_{\rm ch} \rangle$ for minimum-bias \pp , \ppbar , \pPb and central AA  collisions as a function of \snn are shown. The $s_{\mathrm{NN}}$-dependencies of INEL \pp (\ppbar) and NSD \pp (\ppbar) collisions are proportional to $s_{\mathrm{NN}}^{0.120}$ and $s_{\mathrm{NN}}^{0.127}$ respectively. The results from central AA collisions are proportional to $s_{\mathrm{NN}}^{0.192}$. The bands represent the uncertainties on the extracted power-law dependencies.