\begin{table}%t2
   %\centering
\par
   \caption{$R-J$ colour distribution. {The two values represent the total 
number of EROs in the specified magnitude interval and the fraction which has an optical counterpart.}}
\label{tab2}
  \begin{tabular}{clcl}
\hline\hline
                      &                             &       & \\
$J$-magnitude           &  mean $R-J$ colour            &       {\it FWHM}     & ~~~~~EROs~~~~ \\ 
\par
\hline                      14 $\le J <$ 15       & ~~~ 1.68 $\pm$ 0.01         &~~~~~~~0.388 $\pm$ 0.008   &~~~~~~~~~~~0\\
15 $\le J <$ 16       & ~~~ 1.73 $\pm$ 0.01         &~~~~~~~0.473 $\pm$ 0.014   &~~~~~~~~~~~0\\
16 $\le J <$ 17       & ~~~ 1.79 $\pm$ 0.01         &~~~~~~~0.544 $\pm$ 0.024   &~~~~~~~~~~~1/1\\
17 $\le J <$ 18       & ~~~ 1.86 $\pm$ 0.04         &~~~~~~~0.837 $\pm$ 0.090   &~~~~~~~~~~~9/9\\
18 $\le J <$ 19       & ~~~ 3.08 $\pm$ 0.02         &~~~~~~~1.679 $\pm$ 0.020   &~~~~~~~~~41/21\\
                      & ~~~ 5.16 $\pm$ 0.06         &~~~~~~~0.637 $\pm$ 0.066   & \\
19 $\le J <$ 20       & ~~~ 2.85 $\pm$ 0.03         &~~~~~~~1.489 $\pm$ 0.028   &~~~~~~~~~~~9/4\\
                      & ~~~ 4.30 $\pm$ 0.00 (fixed) &~~~~~~~1.656 $\pm$ 0.127   &                 \\         
\hline
\end{tabular}
\end{table}