\begin{table}%t1
\caption{XCOUNT predicted X-ray counts using different stellar
         birthrates, compared with the observations.
\label{tab:model_obs}}
\small
%\centerline
 {\begin{tabular}{l l c c c c c c c}
\hline\hline
                  & B & A & F0-F6 & F7-G & K  & M0-M5 & Total & Range$^\dag$\\
\hline
Observed$^\ddag$   & 1 & 2 &  9    &  9   & 21 & 14    & 56 \\
%$\tau = \infty$   & - & 1 &  2    &  4   &  8 & 10    & 25 \\
%$\tau =  15$ Gyr  & - & 1 &  2    &  6   & 10 & 15    & 34 \\
%$\tau =   5$ Gyr  & - & 1 &  2    &  8   & 13 & 22    & 46 \\
%$\tau = -15$ Gyr  & - & 1 &  2    &  4   &  8 &  9    & 24 \\
Constant birthrate ($\tau = \infty$)            & -- & 2 & 3 & 5 & 7 & 14 & 31 & 19--43\\
Slowly decreasing birthrate ($\tau =  15$ Gyr)  & -- & 2 & 3 & 4 & 6 & 11 & 26 & 15--35\\
Rapidly decreasing birthrate ($\tau =   5$ Gyr) & -- & 2 & 3 & 3 & 5 &  7 & 20 & 12--28\\
Slowly increasing birthrate ($\tau = -15$ Gyr)  & -- & 2 & 3 & 6 & 8 & 18 & 37 & 24--51\\
\hline
\end{tabular}}
\par
\smallskip
{\small
$^\dag$ Range of total number of stars predicted by the model, for 
        each stellar birthrate. This value has been estimated taking the relative
        error on the predicted source counts and the statistical uncertainties 
        in the model simulation into account.\\
$^\ddag$ The two binary systems containing a white dwarf
        (see Sect.~\ref{sec:cross}) have been discarded for
        the comparison.
}
\end{table}