\begin{table}%t2
\caption{\label{table2}Observation statistics of the candidate samples. }


\small%\centerline
 {
\begin{tabular}{lcccc}
\hline\hline
   & RR~143 & RR~210 & RR~216 & RR~242\\
\hline
Candidate sample & 171 & 190 & 178 & 118 \\
Observed & 106 (62\%) & 55 (29\%)& 24 (13\%) & 73 (62\%)\\
Measured z total & 84 (79\%) & 52 (95\%) & 22 (92\%) & 55 (75\%) \\
Measured z {\tt xcsao} & 69 & 50 & 22 & 45 \\
Measured z {\tt splot} & 15 & 2 & -- & 10 \\
Members & 2 (2\%) & 2 (4\%) & 3 (14\%) & 10 (18\%) \\
Members corr. & 4.4 & 4.9 & 15 & 15.4 \\
\multicolumn{4}{l}{{\bf Total number of spectroscopically observed objects}:} & \multicolumn{1}{l}{\bf 258} \\
\multicolumn{4}{l}{{\bf Total number of measured redshifts}:} & \multicolumn{1}{l}{\bf 213 (83\%)} \\
\hline
\end{tabular}}
\medskip
Row 1: number of galaxies in the candidate sample;
row~2: number of galaxies observed with VIMOS, in brackets the percentage of  spectroscopically observed galaxies out of the candidate sample;
row~3: number of galaxies for which a redshift could be measured, in brackets the percentage of galaxies with measured redshift out of all  spectroscopically observed galaxies;
row~4: number of redshifts obtained by cross-correlation with {\tt xcsao};
row~5: number of redshifts obtained by fitting single lines with {\tt splot};
row~6: number of newly discovered members, in brackets the percentage of newly found member galaxies out of all galaxies with measured redshifts;
row~7: completeness corrected number of members (see Sect.~\ref{results}).
\end{table}