\begin{table}%t4
  %\centering
\par
\caption{\label{tab:nc}Cumulative number counts based on the central 10~arcminutes of our map.}
  \begin{tabular}{c c c c}
    \hline \hline \noalign{\smallskip }
    $S_{870}$  &  $N(>S)$ & $N_{\rm sources}$\tablefootmark{a} &
    $N_{\rm per~bin}$\tablefootmark{b} \\
     mJy & deg$^{-2}$ & &\\
    \hline
    0.64 & $>$1970 & 13 & 3 \\
        2.0 & $\rm 1510_{-360}^{+540}$ & 10 & 6 \\[1mm]
        4.0 & $\rm 610_{-250}^{+440}$ & 4 & 3 \\[1mm]
        8.0 & $\rm 150_{-130}^{+350}$ & 1 & 1 \\[1mm]
    \hline   
  \end{tabular}
  \tablefoot{\tablefoottext{a}{Cumulative number of
    sources.} 
    \tablefoottext{b}{The number of sources contributing to
    a bin (used to estimate the uncertainty).}}
  \end{table}