\begin{table}%t3
\caption{\label{table3}Comparison of $A$-value data sets for
Fe~{\sc xviii}--Fe~{\sc xxiv} in terms of mean ratios.}
%\centerline
{
\begin{tabular}{llllllll}
\hline\hline\noalign{\smallskip}
\multicolumn{1}{c}{Data sets$^{{\rm a}}$}&\multicolumn{1}{c}{Fe~{\sc xxiv}}&\multicolumn{1}{c}{Fe~{\sc xxiii}}&\multicolumn{1}{c}{Fe~{\sc xxii}}&
\multicolumn{1}{c}{Fe~{\sc xxi}}&
\multicolumn{1}{c}{Fe~{\sc xx}}&\multicolumn{1}{c}{Fe~{\sc xix}}&\multicolumn{1}{c}{Fe~{\sc xviii}}\\
\noalign{\smallskip}\hline\noalign{\smallskip}
$\overline{R}({\rm AST1,AST2})$ & $0.95\pm 0.09$ & $0.98\pm 0.15$ & $1.01\pm 0.15$ & $1.00\pm 0.12$$^{{\rm b}}$ & $1.00\pm 0.12$ & $1.04\pm 0.08$ & 1.00 \\
$\overline{R}({\rm AST2,AST3})$ & $1.01\pm 0.08$ & $1.00\pm 0.17$$^{{\rm c}}$ & $1.00\pm 0.07$ & $0.99\pm 0.11$$^{{\rm d}}$ & $1.00\pm 0.08$ & $1.00\pm 0.02$ & 1.00 \\
$\overline{R}({\rm HFR3,AST3})$ & $0.96\pm 0.13$ & $1.00\pm 0.16$ & $1.00\pm 0.16$ & $1.00\pm 0.17$ & $1.01\pm 0.16$ & $1.09\pm 0.07$ & 1.05 \\
$\overline{R}({\rm HFR4,AST3})$ & $1.03\pm 0.13^{{\rm e}}$ & $1.06\pm 0.13$ & $1.05\pm 0.10$ & $ 1.05\pm 0.09$ & $ 1.05\pm 0.08$ & $ 1.06\pm 0.03$ & 1.06 \\
$\overline{R}({\rm COR,AST3}) $ & $0.96\pm 0.09$ & $1.01\pm 0.17$ & $0.95\pm 0.16$ & $0.95\pm 0.23$$^{{\rm f}}$ &                &                &                        \\
$\overline{R}({\rm SAF,AST3}) $ & $1.02\pm 0.04$ & $1.00\pm 0.23$$^{{\rm g}}$ & $0.96\pm 0.16$$^{\rm h}$ & $1.00\pm 0.18$$^{{\rm i}}$ &                &                &      \\
$\overline{R}({\rm MCDF,AST3})$ & $0.95\pm 0.05$ & $1.03\pm 0.17$$^{{\rm j}}$ & $0.96\pm 0.14$$^{{\rm k}}$ & $1.18\pm 0.28$$^{{\rm l}}$ &                &                &       \\
\hline
\end{tabular}}
\smallskip
\begin{list}{}{}
\item[$^{{\rm a}}$]Comparison includes only transitions with $\log A_{\rm r}>13$.
\item[$^{{\rm b}}$]Excludes transitions (6;29,3--4) and (6;26,4).
\item[$^{{\rm c}}$]Excludes transition (4;20,4).
\item[$^{{\rm d}}$]Excludes transitions (6;26,3--4), (6;28,2) and (6;29,4).
\item[$^{{\rm e}}$]Excludes transition (3;19,2).
\item[$^{{\rm f}}$]Excludes transitions (6;23,4), (6;26,4) and (6;29,4).
\item[$^{{\rm g}}$]Excludes transitions (4;25--24,3), (4;20,4) and (4;24,4)
in Table~\ref{table4}.
\item[$^{{\rm h}}$]Excludes transitions (5;43,13), (5;46,15) and (5;49,15)
in Table~\ref{table4}.
\item[$^{{\rm i}}$]Excludes transitions (6;26,3--4) and (6;29,4)
in Table~\ref{table4}.
\item[$^{{\rm j}}$]Excludes transitions (4;20,4) and (6;38,9)
in Table~\ref{table5}.
\item[$^{{\rm k}}$]Excludes transitions (5;$k$,$i$) in Table~\ref{table5}.
\item[$^{{\rm l}}$]Excludes transitions (6;$k$,$i$) in Table~\ref{table5}.
\end{list}
\end{table}