Consider the following example:
\documentclass{article}
\usepackage{booktabs,dcolumn,ragged2e}
\newcolumntype{d}[1]{D{.}{,}{#1}}
\newcommand*\mc[1]{\multicolumn{1}{c}{#1}}
\begin{document}
\begin{table}
\centering
\begin{tabular}{>{\RaggedRight\arraybackslash}p{4.4cm} d{2.1} d{2.1} d{2.1} d{2.1} d{2.1} d{2.1} d{2.1} d{2.1} d{2.1}}
\toprule
\mc{{\AA}rstal} & \mc{1997} & \mc{1998} & \mc{1999} & \mc{2000} & \mc{2001} & \mc{2002} & \mc{2003} & \mc{2004} & \mc{2005} \\[1ex]
Antal passagerer i mio., som lufthavnen kan betjene
& 17.1 & 17.8 & 19.9 & 22.7 & 22.7 & 25.2 & 25.2 & 25.2 & 28.0 \\
Forventet {\aa}rligt passagertal i mio.
& 16.6 & 17.4 & 18.2 & 19.0 & 20.0 & 20.9 & 22.0 & 23.1 & 24.2 \\
\bottomrule
\end{tabular}
\end{table}
\end{document}

How do I vertically center the numbers relativt to the blocks of text in the first column? Now, the numbers are vertically aligned at the top of the ``double lines''.
