Measured second cumulants of net-proton distributions (red solid boxes) compared with the sum of the mean multiplicities (open squares). The second cumulants of single proton and antiproton distributions are presented with the filled and open circles, respectively. The first cumulants of protons and antiprotons are hardly distinguishable because of the nearly equal mean numbers of protons and antiprotons at LHC energy. In the middle and bottom panels the normalized cumulants R$_{1}$and R$_{2}$ are presented. The band visible in the bottom panel is the prediction for R$_{2}$ in the presence of volume fluctuations