\begin{table}%t4
\caption{The percentage difference between the damping timescales
in Tables~\ref{table2a} and~\ref{table2b}.}\label{table3}
%\centering
\small
\begin{tabular}{@{\extracolsep{\fill}}c c c c c c c}
\hline \hline
&0.5~(MK)&1.0&2.0&4.0&8.0\\
\hline
&&&&& \\[-8pt]
$2\times10^9$~cm&0.6\%&9.5\%&7.0\%&...&...\\
$4\times10^9$&11.7\%&8.8\%&4.1\%&...&...\\
$8\times10^9$&9.8\%&8.0\%&6.5\%&6.5\%&2.5\%\\
$16\times10^9$&2.0\%&7.2\%&3.7\%&1.7\%&3.9\%\\
\hline
\end{tabular}
\end{table}