\begin{table}%t10
\caption{Flux ratios for the center of the Milky Way, NGC~253, Henize~2-10 and the Cloverleaf~QSO.}\label{tab:rapflu}
%\begin{center}
\par
\begin{tabular}{c|cccc}
\hline\hline
 $F$ & Milky Way & NGC~253 & Henize~2-10 & Cloverleaf \\
(W~m$^{-2}$)&&&&\\
\hline
$\frac{{\rm CI}(^{3}{\rm P}_{1}-^{3}{\rm P}_{0})}{{\rm CI}(^{3}{\rm P}_{2}-^{3}{\rm P}_{1})}$  & 1.00 & 1.15 & Not observed & 0.42\\
%\hline
$\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(1-0)}$ & 7.37 & 22 & 18.75 & $\ge$28.6\\
%\hline
 $\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(2-1)}$ & 1.84 & 2.32 & 3.6 & -- \\
%\hline
$\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(4-3)}$  & 0.67 & 0.34 & 0.64 & 0.47\\
%\hline
 $\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(5-4)}$  & 0.72 & 0.21$^{*}$ & 0.27$^{*}$ & 0.33\\
%\hline
 $\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(6-5)}$  & 1.03 & 0.20 & 0.31 & -- \\
%\hline
$\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(7-6)}$ & 1.18 & 0.26 & 0.23 & 0.12\\
%\hline
$\frac{^{12}{\rm CO}(3-2)}{^{12}{\rm CO}(8-7)}$ & 1.09 & 0.66$^{*}$ & 0.18$^{*}$ & -- \\
\hline
 \end{tabular}
%\end{center}
\par
$^{*}$~These values are computed from PDR~models.
\end{table}