(c) The table below gives the average sea level, \( S \), in the coastal city as a function of the year, \( x \). Complete the missing values.
\begin{tabular}{l|l|l|l|l|l|l}
\hline \( \mathbf{x} \) & \multicolumn{2}{|c|}{1892} & \( \mathbf{i} \) & & 1942 & 1967 \\
\hline \( \mathbf{S} \) & \( \mathbf{i} \) & & 6.982 & \( \mathbf{i} \) & 6.991 & \( \mathbf{i} \) \\
\hline
\end{tabular}