\begin{table}%t1
%\centering
\par
\caption{Number distribution of our quasar sample
         among the redshift and the absolute magnitude bins.
\label{table:01}}
\begin{tabular}{c c c c c c r}
\hline\hline
 &
 $2.0 \leq z < 2.5$ &
 $2.5 \leq z < 3.0$ &
 $3.0 \leq z < 3.5$ &
 $3.5 \leq z < 4.0$ &
 $4.0 \leq z < 4.5$ &
 Total \\
\hline 
$-24.5 > M_B \geq -25.5$ &  643 &  50 &   1 &   0 &   0 &  694 \\
$-25.5 > M_B \geq -26.5$ & 1497 & 284 & 332 & 153 &  25 & 2291 \\
$-26.5 > M_B \geq -27.5$ &  917 & 385 & 323 & 222 & 120 & 1967 \\
$-27.5 > M_B \geq -28.5$ &  105 &  71 &  76 &  53 &  45 &  350 \\
$-28.5 > M_B \geq -29.5$ &    5 &  11 &  16 &   5 &   3 &   40 \\
$-29.5 > M_B \geq -30.5$ &    0 &   1 &   1 &   0 &   0 &    2 \\
total                    & 3167 & 802 & 749 & 433 & 193 & 5344 \\
\hline
\end{tabular}
\end{table}