\begin{table}%t2
%\centering
\par
%tab.2
\caption{Daily sunspot areas in millionths of the solar disk based on NSO-512 data (1974--2003), on NSO-SPM data (1992--2003) and on an independent composite sunspot area data set (1974--2003).}
\label{tab:2}
$$
\begin{tabular}{r@{ vs. }lcr@{ $\pm$ }l}
\hline
\hline
\multicolumn{2}{c}{Comparison} & {$r_{\rm c}$} & \multicolumn{2}{c}{Slope} \\
\hline\noalign{\smallskip}
${A}_{\rm s}^{\rm NSO-512}$ & ${A}_{\rm s}^{\rm comp}$ & 0.948 & 0.733 & 0.006 \\
${A}_{\rm s}^{\rm NSO-SPM}$ & ${A}_{\rm s}^{\rm comp}$ & 0.965 & 0.957 & 0.006 \\
${A}_{\rm s}^{\rm NSO-SPM}$ & $({A}_{\rm s}^{\rm NSO-SPM} - {A}_{\rm pores}^{\rm NSO-SPM})$ & 0.996 & 1.127 & 0.002 \\
\hline
\end{tabular}
$$
\end{table}