\begin{table}%t1 \caption{Sample statistics for various redshift ranges -- (1) the whole sample, (2) the sources for which the LWS aperture subtends $\protect\ga$$10$~kpc, (3) also excluding the two high-redshift quasars \citep{mcc+05,iye+06} and finally, (4) the sources for which the aperture subtends $\protect\la$$10$~kpc.} \label{stats} %\centering \par \begin{tabular}{l c c c} \hline\hline %\noalign{\smallskip} Redshift range & $n$ & $P(\tau)$ & $S(\tau)$\\ %\noalign{\smallskip} \hline \noalign{\smallskip} \multicolumn{4}{c}{$L_{\rm [CII]}/L_{\rm FIR}$-Luminosity distance (Fig.~\ref{ratio-lbt})}\\ \noalign{\smallskip} %\hline \noalign{\smallskip} Whole & 108 &0.0090 & $2.61\sigma$ \\ $z>0.006$ & 63 &0.0022 & $3.06\sigma$ \\ $0.006\leq z\leq0.1296$ & 61 & 0.0114 & $2.53\sigma$ \\ $00.006$ & 63 &$1.1\times10^{-14}$ & $7.73\sigma$ \\ $0.0060.006$ & 63 &$4.1\times10^{-10}$ & $6.25\sigma$ \\ $0.0060.006$ & 63 &$8.1\times10^{-13}$ & $7.16\sigma$ \\ $0.006