\begin{table}%t2
\caption{\label{tab:evol}WMAP sample evolutionary properties.}
%\centerline
 {\small \begin{tabular}{lrllclc}
\hline\hline
 ~&~&~&\multispan2{$H_0 = 70$, $\Omega_{\rm M} = 0.3$, $\Omega_{\rm
 \Lambda} = 0.7$~~~~}& \multispan2{$H_0 = 50$, $\Omega_{\rm M} = 0$,
 $\Omega_{\rm \Lambda} = 0$}\\
  Class & Number & ~~~$\langle z \rangle$ & $\langle V/V_{\rm max} \rangle$
 & $\tau$  & $\langle V/V_{\rm max} \rangle$ & $\tau$ \\
\hline\noalign{\smallskip}
 FSRQ & 137 & $1.13\pm0.05$ & $0.614\pm0.025$ & $0.35^{\rm +0.07}_{-0.05}$
&$0.621\pm0.025$ & $0.26^{\rm +0.05}_{-0.03}$\\
 BL Lacs & 24 & $0.56\pm0.09^a$ & $0.619\pm0.059^b$ & $0.31^{\rm +0.21}_{-0.08}$
&$0.626\pm0.059^b$ & $0.24^{\rm +0.15}_{-0.05}$\\
 Radio Galaxies & 15 & $0.08\pm0.04$ & $0.610\pm0.074$ & ...$^c$
&$0.610\pm0.074$ & ...$^c$\\
 Unclassified blazars & 11 & $0.77\pm0.16^d$ & $0.703\pm0.087^e$ & $0.22^{\rm +0.11}_{-0.04}$
&$0.713\pm0.087^e$ & $0.17^{\rm +0.07}_{-0.03}$ \\
 SSRQ & 9 & $0.50\pm0.14$ & $0.626\pm0.096$ & ...$^c$
&$0.632\pm0.096$ & ...$^c$\\
\hline
\end{tabular}}
$^a$ Excluding the 6 sources without redshift; $^b$ assuming $z = \langle z \rangle$ for the sources  without redshift; $^c$ $\langle V/V_{\rm max} \rangle$ not significantly different ($<$2$\sigma$) from 0.5: no evolution assumed;  $^d$~excluding the 6 sources without redshift; $^e$~assuming $z$  equal to the mean blazar redshift for  the sources without redshift.
\end{table}