\begin{table}%t2
\caption{\label{tab:surveys}Name, year, number of detected pulsars ($N_{\rm real}$),
  number of simulated detected pulsars   ($N_{\rm sim}$) and frequency observed at ($\nu$) for the eight  surveys simulated. }
\par
%\centerline
{
  \begin{tabular}{lcccc}
  \hline \hline
  Survey & Year      & $N_{\rm real}$&  $N_{\rm sim}$ & $\nu$ (MHz) \\
  \hline 	        				    Jodrell                & 1972      & 51    &   20 $\pm$   2 &  408 \\
  UMass-Arecibo          & 1974      & 50    &   39 $\pm$   4 &  430 \\
  MolongloII             & 1978      & 224   &  227 $\pm$   7 &  408 \\
  UMass-NRAO             & 1978      & 50    &   54 $\pm$   6 &  400 \\
  ParkesII               & 1991--1994 & 298   &  335 $\pm$  10 &  400 \\
  Cambridge 80MHz        & 1993--1994 &  20   &   27 $\pm$   5 &   82 \\
  Parkes Multibeam       & 1997--2000 &   987 &  801 $\pm$  41 & 1374 \\
  LOFAR                  & 2010--2012 & --    & 1100 $\pm$ 100 &  140 \\
  \hline
  \end{tabular}}
   \medskip
\par
 The error on $N_{\rm sim}$ is the standard
  variation in the outcomes when simulating the model described in the
  text with different random number seeds. The $N_{\rm real}$ data
  is taken from \citet{dls77,ht75b,mlt+78,dth78,mld+96,stw98} and \citet{mhth05}
  respectively. The LOFAR numbers are for the incoherent 25-day reference design
  described in the text.
  \end{table}