\begin{tabular}{rrrr}
  \hline
  Method & 
  Compression Ratio & 
  Compression Time & 
  Decompression Time \\
  \hline
  a & 32.00 & 3.48 & 3.09 \\
  aaa & 0.01 & 0.00 & 0.00 \\
  alphabet & 0.01 & 0.00 & 0.00 \\
  random & 7.30 & 0.01 & 0.01 \\
\end{tabular}
\caption{Results for ppmD7 (sorted by file)}
