https://tex.stackexchange.com/q/437492/35864

hanstable.tex

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\begin{document}
\begin{table}[htbp]
\centering
\caption{MAE for 48 irradiance transposition pathways}
\label{tab:MAE results}

\begin{tabular}{l*{3}{S[table-format = 2.2]}}
    \toprule
    & \multicolumn{3}{c}{Transposition}\\
    \cmidrule(lr){2-4}
    Decomposition & {DIRINT} &  {DISC} &  {Erbs}   \\ \midrule
    Reindl                                      &   8,11 & 16,79 & 21,79   \\
    Hay \& Davies                               &   8,11 & 16,75 & 21,75   \\
    P. Albuquerque   1988                        &   8,33 & 17,39 & 23,34   \\
    P. Phoenix 1988                              &   8,34 & 17,39 & 23,22   \\
    P. Sandia composite 1988                     &   8,39 & 17,38 & 23,16   \\
    King                                        &   8,41 & 16,75 & 20,52   \\
    P. Cape Canaveral 1988                       &   8,50 & 17,55 & 22,53   \\
    P. USA composite 1988                        &   8,51 & 17,51 & 22,98   \\
    P. Osage 1988                                &   8,55 & 17,87 & 24,03   \\
    P. All sites composite 1990                  &   8,58 & 17,61 & 22,79   \\
    Isotropic sky                               &   8,59 & 16,20 & 20,70   \\
    P. Albany 1988                               &   8,65 & 17,54 & 22,72   \\
    P. Elmonte 1988                              &   8,65 & 17,61 & 23,26   \\
    P. All sites composite 1988                  &   8,74 & 17,79 & 23,06   \\
    P. France 1988                               &   9,23 & 18,17 & 23,02   \\
    Klucher                                     &  10,38 & 20,02 & 23,53   \\ \midrule
    Column average                              &   8,63 & 17,52 & 22,65   \\ \bottomrule
\end{tabular}
\end{table}
\end{document}