Values of $f(x,y)$ are given in the table below. Let $R$ be the rectangle $1 \leq x \leq 1.6, 2 \leq y \leq 3.2$. Find a Riemann sum which is a reasonable estimate for $\int_R f(x,y) \, da$ with $\Delta x = 0.2$ and $\Delta y = 0.4$. Note that the values given in the table correspond to midpoints.

$$\begin{array}{|c || c|c|c|} \hline y \backslash x & 1.1 & 1.3 & 1.5 \\ \hline \hline 2.2 & -2 & 4 & -3 \\ \hline 2.6 & 7 & 10 & 3 \\ \hline 3.0 & -2 & 6 & 1 \\ \hline \end{array}$$

$\int_R f(x,y) \, da \approx$