\begin{table}%t1
\caption{Temporal variation in multipole moments.}\label{tab1}
%\centering
\small
\begin{tabular}{ccccccc}
\hline
\hline
$k$&\multispan2{\hfill $\langle J_k\rangle$\hfill}&
\multispan2{\hfill Phase (years)\hfill}&
\multispan2{\hfill $|\delta J_k|$\hfill}\\
&GONG&MDI&GONG&MDI&GONG&MDI\\
\hline
&&&&&& \\[-8pt]
2&$(2.18\pm0.005)\times10^{-7}$&$(2.22\pm0.009)\times10^{-7}$
&$4.1$&\phantom{1}$8.7$&
$1.0\times10^{-10}$&$9.5\times10^{-11}$\\
4&$-(4.70\pm0.06)\times10^{-9}$&$-(3.97\pm0.09)\times10^{-9}$
&$1.4$&\phantom{1}$0.1$&
$4.9\times10^{-11}$&$7.9\times10^{-11}$\\
6&$-(2.4\pm0.2)\times10^{-10}$&$-(0.8\pm0.3)\times10^{-10}$
&$7.3$&$10.7$&
$4.8\times10^{-12}$&$1.3\times10^{-11}$\\
8&$-(0.8\pm0.6)\times10^{-11}$&$\phantom{-}(1.1\pm0.9)\times10^{-11}$
&$4.5$&\phantom{1}$3.6$&
$1.6\times10^{-11}$&$1.7\times10^{-11}$\\
10&$\phantom{-}(7.1\pm4.0)\times10^{-12}$&$\phantom{-}(7.4\pm4.0)\times10^{-12}$
&$1.6$&\phantom{1}$1.4$&
$7.3\times10^{-12}$&$7.8\times10^{-12}$\\
12&${-}(1.9\pm2.4)\times10^{-12}$&${-}(1.8\pm2.0)\times10^{-12}$
&$6.8$&\phantom{1}$6.9$&
$3.2\times10^{-12}$&$2.6\times10^{-12}$\\
\hline
\end{tabular}
\end{table}