\begin{table}%t1
\par
\caption{\label{table:1}Summary of previous high angular resolution studies of 6.7~GHz methanol masers.}
%\centerline
 {\begin{tabular}{lcccccc}
\hline\hline 
Survey & Telescope & Spectral resolution & Angular resolution &  1$\sigma_{{\rm rms}}$ & Number of targets & Median peak flux 
density \\ 
       &           & (km~s$^{-1}$)       &  (mas)             & (mJy~beam$^{-1}$) & &  (Jy) \\
\hline
Norris et~al. (1993)  & ATCA& 0.3 & 1500    & $\sim$500 & 15 & 475 \\
Phillips et~al. (1998)& ATCA& 0.35& 1500   & $\sim$50& 33 & 41 \\
Walsh et~al. (1998)   & ATCA& 0.18& 1500   &       300 & 97 & 23 \\
Minier et~al. (2000)  & EVN & 0.04& few    &        $-^*$  & 14 & 272 \\
Dodson et~al. (2004)  & LBA & 0.2 & 5.3    &         2 &  5 & 148 \\
This paper          & EVN & 0.09; 0.18& $\sim$$6\times14$ &   3$-$12 &  31 &  3.6 \\
\hline 
\end{tabular}}
\par
\smallskip
{$^*$ The value not given.}
\end{table}