\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 & 7.0 & 3.0 & 0.0 & 10.0 \\\hline
Task-4 & HAS front-end & 25.0 & 20.0 & 25.0 & 70.0 \\\hline
\hline
 & total &  32.0 & 23.0 & 25.0 & 80.0 \\\hline
\end{tabular}\end{small}\end{center}