\begin{table}%t6
%\centering
\par
\caption{\label{t:pca}Eigenvalues, fractional, and cumulative contributions for
the two cases discussed in the text.}
\begin{tabular}{rrrrrrrrccrrrrrrrr}
\hline\hline\noalign{\smallskip}
\multicolumn{4}{c}{34 parameters, 15~GCs} && &\multicolumn{4}{c}{21 parameters, 19~GCs}\\
$i$ & $e_i$ & $V_i$ & $C_i$ &&& $i$ & $e_i$ & $V_i$ & $C_i$ &\\
\hline
 1 & 11.35 & 33.39 & 33.39 & & &  1 & 8.25 & 39.30 & 39.30 \\ 
 2 &  5.19 & 15.28 & 48.67 & & &  2 & 3.61 & 17.18 & 56.48 \\ 
 3 &  4.52 & 13.28 & 61.95 & & &  3 & 2.11 & 10.05 & 66.53 \\ 
 4 &  2.99 &  8.79 & 70.73 & & &  4 & 1.86 &  8.83 & 75.36 \\ 
 5 &  2.40 &  7.06 & 77.79 & & &  5 & 1.56 &  7.51 & 82.87 \\ 
 6 &  2.06 &  6.17 & 83.96 & & &  6 & 0.96 &  4.57 & 87.44\\ 
 7 &  1.76 &  5.17 & 89.13 & & &  7 & 0.69 &  3.20 & 90.74 \\ 
 8 &  1.16 &  3.42 & 92.55 & & &  8 & 0.61 &  2.91 & 93.65 \\ 
\hline
\end{tabular}
\vspace*{-4mm}
\end{table}