\begin{table}%t1
\caption{The detection rates of the PAH 3.3~$\mu$m feature in the ISO and ISAAC~samples. T~stands for the total of classified sample sources, I and~II refer to the Meeus groups and~E represents the
  embedded sources. The last
  row gives the detection rates in the combined ISO+ISAAC~sample. When
  two~percentages are given, the second refers to the detection rate
  including tentative detections. The detection rate in group~I is
  significantly higher than in group~II (confidence level  $>$99.5\%).}\label{detectionrates}
%\centering
\small
\begin{tabular}{r|cccc}
\hline \hline
       & T       & I       & II       & E       \\
\hline	                   	      	        
ISO    &22$-$29\%&44$-$56\%& 14\%     & 0$-$14\%     \\
ISAAC  &12$-$18\%&36$-$50\%& 0$-$3\%  & 17\%    \\
total  &14$-$21\%&32$-$48\%& 5$-$7\%  & 9\%     \\
\hline
\end{tabular}
\end{table}