\begin{table}
 %\centering
  \caption{\label{fractionbrightdark}Number of bright (classes 1-4) and 
     dark (5--6) peaks and their ratios for the $S$- and the
     $P$-statistics.}
   \begin{tabular}{lccc|ccc}
   \noalign{\smallskip}
   \noalign{\smallskip}
   \hline 
   \hline 
   \noalign{\smallskip}
   \noalign{\smallskip}
   $S/N$ & $n_{\rm b}(S)$ & $n_{\rm d}(S)$ & $n_{\rm d}/n_{\rm b}$  & 
           $n_{\rm b}(P)$ & $n_{\rm d}(P)$ & $n_{\rm d}/n_{\rm b}$ \\ 
   \noalign{\smallskip}
   \noalign{\smallskip}
   \hline 
   \noalign{\smallskip}
   $4.0-4.25$ & 23 & 31 & 1.3 & 7  & 12 & 1.7 \\
   $4.25-4.5$ & 9  & 11 & 1.2 & 5  & 9  & 1.8 \\
   $4.5-4.75$ & 6  &  5 & 0.8 & 6  & 7  & 1.2 \\
   $4.75-5.0$ & 2  &  0 & 0.0 & 3  & 4  & 1.3 \\
   $5.0-6.0$  & 2  &  1 & 0.5 & 8  & 11 & 1.4 \\
   $>6.0$     & 1  &  0 & 0.0 & 15 & 7  & 0.5 \\
   \hline 
   total      & 43 & 48 & & 44 & 50 & \\
   \hline 
   \end{tabular}
   \normalsize
\end{table}