Left: charged-particle number density in the transverse region as a function of \ptt for pp collisions at $\sqrt{s}= 0.9$, 5.02, 7, and 13\,\TeV . A constant function (solid lines) is used to fit the data in the range $5 < \ptt < 10$\,\GeV/$c$. Right: number densities scaled by the plateau values obtained from the fit to compare the shapes. The coloured boxes represent the systematic uncertainties, and vertical error bars indicate statistical uncertainties.