\begin{longtable}[]{@{}
  >{\centering\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.3000}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.3000}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.2000}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.2000}}@{}}
\caption{States belonging to the \emph{Nordics.}}\tabularnewline
\toprule
\begin{minipage}[b]{\linewidth}\centering
Name
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Capital
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Population\\
(in 2018)\strut
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Area\\
(in km\textsuperscript{2})\strut
\end{minipage} \\
\midrule
\endfirsthead
\toprule
\begin{minipage}[b]{\linewidth}\centering
Name
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Capital
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Population\\
(in 2018)\strut
\end{minipage} & \begin{minipage}[b]{\linewidth}\centering
Area\\
(in km\textsuperscript{2})\strut
\end{minipage} \\
\midrule
\endhead
Denmark & Copenhagen & 5,809,502 & 43,094 \\
Finland & Helsinki & 5,537,364 & 338,145 \\
Iceland & Reykjavik & 343,518 & 103,000 \\
Norway & Oslo & 5,372,191 & 323,802 \\
Sweden & Stockholm & 10,313,447 & 450,295 \\
Total & & 27,376,022 & 1,258,336 \\
\bottomrule
\end{longtable}