Comparison of $\langle $d$E_{\mathrm T}/$d$\eta \rangle$/$\langle $d$N_{\mathrm{ch}}/$d$\eta \rangle$ at midrapidity versus ${\sqrt{s_{\mathrm {NN}}}}$ in Pb-Pb collisions at ${\sqrt{s_{\mathrm {NN}}}}$ = 2.76 TeV from ALICE and measurements at other energies. The band shows the extrapolation from lower energies with the width representing the uncertainty on the fit.