\begin{table}%t3 \caption{\label{table3}Spectral parameters values with their respective statistical errors for a smoothed broken power law shape. The fits are performed in the [160 GeV--70 TeV] energy range.} \par %\centerline { \begin{tabular}{cccccccc} \hline\hline Year & $\Phi_0{}^a$ & $\Gamma_1{}^b$ & $\Gamma_2^{b}$ & $E_{\rm{break}}{}^c$ & $E_{\rm{break,true}}{}^d$ & $I$($\geq$1 TeV)$^e$ & $\chi^{2}$/d.o.f. \\ & $\rm (10^{-12} TeV^{-1} cm^{-2} s^{-1})$ & & & (TeV) & (TeV) & $\rm (10^{-12} cm^{-2} s^{-1})$ & \\ \hline\hline 2004 & 2.39 $\pm$ 0.12 & 2.18 $\pm$ 0.13 & 2.51 $\pm$ 0.23 & 2.40 $\pm$ 0.28 & 2.33 $\pm$ 0.28 & 1.79 $\pm$ 0.58 & 25/19\\ 2005 & 2.64 $\pm$ 0.10 & 1.73 $\pm$ 0.10 & 3.07 $\pm$ 0.26 & 3.35 $\pm$ 0.37 & 3.37 $\pm$ 0.37 & 2.11 $\pm$ 0.60 & 28/18\\ 2006 & 2.28 $\pm$ 0.18 & 2.27 $\pm$ 0.24 & 2.19 $\pm$ 0.28 & 2.04 $\pm$ 0.38 & 1.94 $\pm$ 0.38 & 1.85 $\pm$ 0.87 & 14/18\\ \hline All & 2.57 $\pm$ 0.07 & 2.02 $\pm$ 0.08 & 2.63 $\pm$ 0.14 & 2.61 $\pm$ 0.19 & 2.57 $\pm$ 0.19 & 1.98 $\pm$ 0.38 & 21/19\\ \hline \end{tabular}} \par \medskip $^a$ Flux normalisation. $^b$ Reconstructed spectral index. $^c$ Reconstructed break energy without corrections for the systematic bias. $^d$ Reconstructed break energy corrected for the systematic bias. $^e$ Integrated $\gamma$-ray flux above 1 TeV. \end{table}