\begin{table}%t2
\caption{\label{tab_efficiencies}HFI optical efficiencies assuming top-hat like channel spectral transmissions with nominal bandwidth edges.}
%\centering
\par
\begin{tabular}{l*{10}{c}}
\hline \hline \noalign{\smallskip}
Channel  & & 100P & 143P &143 &217P &217 & 353P & 353 & 545 & 857 \\
\hline
Average efficiency &(\%)&32.2&43.2&28.7 &  31.3&25.7&21.3& 23.4&15.7&13.1\\
Dispersion &(1$\sigma$, \%)&4.1 &3.55 &1.5 &2.7 &1.1 &2.8 &5.8 &1.4 &2.2\\
\hline
\end{tabular}
\end{table}