\begin{center}\begin{small}\begin{tabular}{|c|l||r|r|r||r|}\hline
 & title & \multicolumn{3}{c||}{years } & total \\\cline{3-5}
 &       & \multicolumn{1}{c|}{1} & \multicolumn{1}{c|}{2} & \multicolumn{1}{c||}{3} &  \\\hline\hline
Task-2 & Backbone infrastructure & 9.0 & 4.5 & 0.0 & 13.5 \\\hline
Task-4 & HAS front-end & 9.0 & 12.0 & 25.5 & 46.5 \\\hline
\hline
 & total &  18.0 & 16.5 & 25.5 & 60.0 \\\hline
\end{tabular}\end{small}\end{center}