A stores demand figures are given in the table. According to this, what is the linear regression forecast for Week 12. (You need to use Excel to solve this problem. Do not round intermediate calculations.

\begin{tabular}{|cc|} \hline Week Actual \\ 1 & 15.9 \\ 2 & 34.0 \\ 3 & 42.3 \\ 4 & 47.1 \\ 5 & 58.9 \\ 6 & 68.6 \\ 7 & 76.9 \\ 8 & 85.9 \\ 9 & 96.3 \\ 10 & 103.2 \\ \hline \end{tabular}