\begin{table}

\begin{tabular}{l|l|l|l|l|}
\cline{2-5}
&\multicolumn{2}{|c|}{Within-Company}&\multicolumn{2}{|c|}{Cross-Company} \\ \cline{2-5}
&      Raw&  Logging& Raw & Logging \\ \hline\hline
Ridor& 2.56& 2.52&    3.34& 3.27 \\ \hline
jRip&  2.45& 2.53&    4.06& 4.17 \\ \hline
Clump&    3&    3&        3&   2 \\ \hline
\end{tabular}

\caption{Number of rules}\label{tbl:numberOfRules}
\end{table}
