\begin{table}%t1
\caption{\label{table1}Details of the observation of the GC region with H.E.S.S. for the 2004, 2005 and 2006 observation campaigns.}
%\centerline
{
\begin{tabular}{cccccc}
\hline\hline 
Year & $\theta_z{}^a$ range & $\bar{\theta_z}^{a}$ & $T_{\rm obs}{}^b$ & $ N_{\gamma}{}^c$ & $\sigma^d$\\
& (\degr) & (\degr) & (h) & & \\
\hline 
2004 & 0--60 & 21.3 & 28.5 & 1516 & 35.6 \\
2005 & 0--70 & 26.6 & 51.7 & 2062 & 41.2 \\
2006 & 0--50 & 19.1 & 12.7 & 607 & 23.0 \\
\hline
All  & 0--70 & 23.0 & 92.9 & 4185 & 60.7 \\
\hline
\end{tabular}}
\par
\medskip
$^a$ $\theta_z$ denotes the zenith angle. 
$^b$ Live time of the data sample.
$^c$ Number of detected $\gamma$-rays after background substraction.  
$^d$ Significance of the $\gamma$-ray excess $N_{\gamma}$ calculated according to the prescription of Li and Ma (\cite{LiMa}).
\end{table}