\begin{table}%t1
%\centering
\par
\caption{$m$ values obtained from line profile variations in 3 independent 
datasets.\label{tab1}}
\begin{tabular}{rrrr}
\hline\hline\noalign{\smallskip}
Freq.&\multicolumn{3}{c}{$m$}\\
\cline{2-4}
[\cd]  &1995&1996& 1998\\
\hline
1.47 & 7 & 7 & 8 \\
13.85 & $-$13 & $-$12 & $-$13 \\
14.38 & $-$14 & $-$13 & $-$13 \\
14.94 & $-$13 & $-$15 & $-$13 \\
14.62 & $-$12 & --& --      \\
\hline
\end{tabular}
\end{table}