\begin{table}%t1
\caption{\label{table:correl}Frequency shifts at each $l$ per unit of change in solar proxy and correlations from the analysis of independent 91.25-day GOLF spectra.}
%\centerline
 {\small \begin{tabular}{l r c c r r r r c} 
\hline\hline 
&\multicolumn{4}{c}{April 1996--June 2007} & \multicolumn{4}{c}{June 2007--May 2009}           \\    
$l$ & \multicolumn{1}{r}{Gradient$^a$} & \multicolumn{1}{c}{$r_{\rm p}$} & \multicolumn{1}{c}{$r_{\rm s}$} & \multicolumn{1}{c}{$P_{\rm s}$} & \multicolumn{1}{c}{Gradient$^a$} & \multicolumn{1}{c}{$r_{\rm p}$} & \multicolumn{1}{c}{$r_{\rm s}$} & \multicolumn{1}{c}{$P_{\rm s}$} \\
\hline
&  \multicolumn{8}{c}{ \it{10.7-{\rm cm} radio flux} }        \\  
0 & 1.3 $\pm$ 0.2 & 0.82 &  0.77 & $1.15 \times 10^{-9}$ & $-16.6$ $\pm$ 12.1     &  $-0.66$ & $-0.71$ & 0.07 \\  
1 & 1.7 $\pm$ 0.2 & 0.82 &  0.82 & $1.93 \times 10^{-11}$ & 6.2 $\pm$ 11.5         &  0.52       & 0.43       & 0.34 \\
   2 & 2.1 $\pm$ 0.2 & 0.86 &  0.85 & $5.55 \times 10^{-13}$ & $-26.7$ $\pm$ 13.1 & $-0.48$  & $-0.32$ & 0.48 \\
 &  \multicolumn{8}{c} {\it{Mount Wilson MPSI} }          \\
0 & 57.4 $\pm$ 7.3 & 0.81 & 0.78 & $9.74 \times 10^{-10}$ & $-498.3$ $\pm$ 440.6 &  $-0.58$ & $-0.39$ & 0.38 \\  
   1  & 78.9 $\pm$ 7.0 & 0.83 & 0.85 & $7.37 \times 10^{-13}$ & 239.6 $\pm$ 419.1       & 0.56        & 0.46       & 0.29 \\
   2  & 96.0 $\pm$ 7.8 & 0.85 & 0.84 & $2.63 \times 10^{-12}$ & $-827.3$ $\pm$ 457.1 & $-0.44$  & $-0.07$ & 0.88 \\
\hline         
\end{tabular}}
\medskip
$^a$ Gradient against the radio flux in units of nHz RF$^{-1}$ (with 1~RF =  10$^{-22}$~J~s$^{-1}$~m$^{-2}$~Hz$^{-1}$); against the MPSI in units of nHz~G$^{-1}$.
\end{table}