\begin{table}%t2
\caption{\label{frac:star}Fraction of $HK_{\rm s}L$ sources with a NIR excess. We also list the
        fraction derived by selecting only $HK_{\rm s}L$ sources whose $K_{\rm s}$,
        after correction for reddening as explained in Sect.~\ref{frac:def}
        ($K_{\rm dered}$), is less than given thresholds
        (the selection criteria for $L$ and $K_{\rm dered}$ are indicated
        in the first line).}     
%\centering
\par
\begin{tabular}{c c c c c c c c}        
\hline\hline  \noalign{\smallskip}             
      & \multicolumn{2}{c}{$L < L_{\rm compl}''$} & 
            \multicolumn{2}{c}{$L < L_{\rm compl}$} &
             \multicolumn{2}{c}{$L < L_{\rm compl}$ and $K_{\rm dered} < 14$} & 
             \multicolumn{1}{c}{$L < L_{\rm compl}$ and $K_{\rm dered} < 11$} \\
Field & Fraction & Fraction & Fraction & Fraction &
        Fraction & Fraction & Fraction \\    % table heading
name  & corrected & uncorrected & corrected  & uncorrected  &
       corrected & uncorrected & uncorrected \\
\hline                        % inserts single horizontal line
IRS16 & $0.74 \pm 0.18$ & $0.65 \pm 0.16$ & $0.65 \pm 0.13$ & $0.60 \pm 0.11$ & 
         $0.60 \pm 0.12$ & $0.56 \pm 0.11$ & $0.46 \pm 0.25$ \\ 
IRS17 & $0.93 \pm 0.30$ & $0.65 \pm 0.23$ & $0.66 \pm 0.18$ & $0.57 \pm 0.15$ & 
         $0.59 \pm 0.16$ & $0.50 \pm 0.14$ & $0.56 \pm 0.31$ \\ 
IRS18 & $0.73 \pm 0.13$ & $0.68 \pm 0.13$ & $0.66 \pm 0.11$ & $0.63 \pm 0.10$ & 
         $0.62 \pm 0.11$ & $0.59 \pm 0.10$ & $0.43 \pm 0.21$ \\ 
IRS20 & $0.91 \pm 0.28$ & $0.68 \pm 0.23$ & $0.73 \pm 0.17$ & $0.63 \pm 0.15$ & 
         $0.66 \pm 0.17$ & $0.56 \pm 0.15$ & $0.25 \pm 0.28$ \\ 
IRS21 & $0.69 \pm 0.22$ & $0.52 \pm 0.19$ & $0.49 \pm 0.12$ & $0.43 \pm 0.11$ & 
         $0.46 \pm 0.11$ & $0.41 \pm 0.11$ & $0.29 \pm 0.16$ \\ 
IRS22 & $0.87 \pm 0.24$ & $0.66 \pm 0.20$ & $0.69 \pm 0.16$ & $0.62 \pm 0.13$ & 
         $0.67 \pm 0.15$ & $0.60 \pm 0.14$ & $0.50 \pm 0.22$ \\ 
\hline                                   %inserts single line
\end{tabular}
\vspace*{2.8mm}
\end{table}