\begin{table}%t5
\caption{\label{Avg_Grt}Average spectral gradients for TNOs and Centaurs.}  
\small%\centerline
 {
\begin{tabular}{c c c}  
\hline\hline  
& Grt & $n$\\
& (\%$/100$ nm)& \\
  \hline  
Classical & 22.9 $\pm$ 9.8 & 73\\  
Hot	    & 19.6 $\pm$ 8.5 & 42\\
Cold	& 27.4 $\pm$ 11.3 & 31\\	
\hline
SDOs	& 18.6 $\pm$ 7.6 & 25\\
\hline
Centaurs    & 19.8 $\pm$ 6.7 & 18\\
\hline  
\end{tabular}}
\medskip
Average spectral gradients for the different dynamical groups (except resonant objects) calculated for the whole sample: OWN+LP+2MS. Grt, is the spectral gradient calculated as explained in Sect.~\ref{Grt}. The errors give the statistical error of the average color and fitted 
spectral gradient values, respectively. $n$,~is the total number of objects used in the average calculation.
\end{table}