\begin{table}%t4
\caption{Cluster and field-star statistics.}
\label{tab4}
\small%\centerline
{
\begin{tabular}{lrrrrrrr}
\hline\hline
&\multicolumn{3}{c}{M~52}&&\multicolumn{3}{c}{NGC~3960}\\
\cline{2-4}\cline{6-8}
$\Delta R$&$N_{\rm obs}$&$f_{\rm cl}$&$f_{\rm fs}$& &$N_{\rm obs}$&$f_{\rm cl}$&$f_{\rm fs}$ \\
 (\arcmin)&(stars)&(\%)&(\%)&&(stars)&(\%)&(\%)\\
   (1)   &(2)    &(3) &(4) &&(5)    &(6) &(7)\\
\hline
0--3&313&63&37&&210&51&49\\
3--6&601&43&57&&434&28&72\\
6--9&726&21&79&&582&11&89\\
9--12&874&8&92&&803&9&91\\
12--15&1053&2&98&&927&0&100\\
Total field&3567&20&80&&2029&18&82\\
\hline
\end{tabular}}
\medskip
Notes. Columns~2 and~5: number of observed stars in the region; Cols.~3 and~6: fraction of
member stars; Cols.~4 and~7: fraction of field stars. Total field is $R=15\arcmin$ for M~52 
and $R=12\arcmin$ for NGC~3960.
\end{table}