\begin{table}%t1
%\centering
\par
      \caption{Parameters of Stokes~$V$~class profiles. The first column
      represents the class number (see text). The second column is the number of the profiles
      belonging to each class. $B$ and~$v_{\rm zc}$ are, respectively,
      their average intrinsic magnetic field strength and Stokes~$V$ zero-crossing
      wavelength (positive means downflow). The last three columns are the average~$V$
      amplitude and
      the average asymmetries of Stokes~$V$ amplitude and
      area (see Sect.~\ref{sec:asymmetry}).\label{param}}
\par
         \begin{tabular}{ccccccc}
            \hline\hline
            \noalign{\smallskip}
            Class      &  $N$ of profiles & $B$  &  $v_{\rm zc}$    &
            Amplitude  & Ampl.~  asym.  &  Area asym.  \\
              $ $      & [\%]           & [G]  &  [km s$^{-1}$] & [$10^{-3}
              I_{\rm c}$] & [\%] & [\%] \\
            \noalign{\smallskip}
            \hline
            \noalign{\smallskip}
       1     &    30 $\pm$ 13  & 470   &  $ 0.2$     &  1.98 &   27        &   6  \\
       2     &    15 $\pm$ 7   & 300   &  $ $0.3     &  2.08 &  9         &   2  \\
       3     &    12 $\pm$ 5   & 280   &  $-$1.3     &  1.95 &   $-7$       &   13  \\
       4     &    12 $\pm$ 6   & 610   &   $1.7$     &  1.65 &   21       &    1  \\
       5     &    11 $\pm$ 4   & 370   &   $1.6$     &  1.49 &    26       &   $-4$  \\
       6     &    11 $\pm$ 7   & 490   &  $-$1.2     &  2.00 &    27       &   12  \\
       7     &    5  $\pm$ 1   & 370   &  $-$3.0     &  1.84 &    $-$       &   $-$  \\
       8     &    3  $\pm$ 1   & 320   &   $3.7$     &  1.37 &    $-$       &   $-$  \\
            \hline
         \end{tabular}
\par
   \end{table}