\begin{table}%t5
\caption{\label{tab:abundhe}Relative abundances $n_{\xi} / n_{{\rm b}}$ of helium species at redshifts $z=1000$, $z=100$ and $z=10$ in the SBBC model}
%%\centering

\par
\begin{tabular}{l l l l l}
\hline
\hline
& & & SBBC &\\
\hline
Species && $z=1000$ & $z=100$ & $z=10$\\
\hline
$[{\rm He}]$ && 0.111 & 0.111 & 0.111\\
$[{\rm He}^+]$ && $3.0 \times 10^{-20}$ & $3.3 \times 10^{-25}$ & $9.1 \times 10^{-26}$\\
$[{\rm HeH}^+]$ && $1.4 \times 10^{-22}$ & $7.2 \times 10^{-15}$ & $4.6 \times 10^{-14}$\\
\hline
\end{tabular}
\end{table}