\begin{table}%T2
%\centering
 \caption{Number of months that are found to be 
significant in the activity excess of one hemisphere over the
other, separately for each solar cycle. The calculation was
performed on a 99\%-level applying the Student's t-test given in
Eq.~(\ref{t-test}).}
\label{stud-tab}  
\begin{tabular}{lccc}
\hline \hline
 Cycle    & fraction of  &    \multicolumn{2}{c}{months of excess}  \\
          & asymmetry    &     \multicolumn{2}{c}{per cycle}        \\
          & per cycle \%    &     North no.~(\%)  &  South no.~(\%)    \\ \hline
cycle 18  &  50 &    25 (25) &  25 (25)   \\ cycle 19  &  58 &
69 (50) &  11 ( 8)   \\ cycle 20  &  63 &    60 (43) &  28 (20)
\\ cycle 21  &  50 &    30 (24) &  32 (26)   \\ cycle 22  &  52 &
21 (18) &  40 (34)   \\ cycle 23  &  47 &    17 (17) &  31 (30)
\\  \hline
\end{tabular}
\end{table}