How to calculate for the Year 2018? And the Year 2019? And what is the Excel Formula for the Year 2018 and 2019?

\begin{tabular}{|c|c|c|c|c|c|c|c|c|} \hline \begin{tabular}{c} Products/ \\ Services \end{tabular} & 2016 & 2017 & \begin{tabular}{l} Rate of \\ Change \end{tabular} & 2018 & 2019 & \begin{tabular}{c} Average \\ Sales from \\ 20162019 \end{tabular} & \begin{tabular}{l} Total \\ Sales for \\ 2016-2019 \end{tabular} & \begin{tabular}{l} Market Share \\ for 2017 \end{tabular} \\ \hline \begin{tabular}{l} Banana \\ Muffin \end{tabular} & $8,500.00 & $11,050.00 & 0.3 & & & & & 36% \\ \hline \begin{tabular}{l} Chocolate \\ Chip \\ Muffin \end{tabular} & $7,360.25 & $8,000.00 & 0.09 & & & & & 26% \\ \hline \begin{tabular}{l} Lemon- \\ raspberry \\ streusel \\ Muffin \end{tabular} & $6,107.14 & $5,655.14 & -0.07 & & & & & 18% \\ \hline \begin{tabular}{l} Cinnamon \\ Muffin \end{tabular} & $5,500.17 & $4,600.25 & -0.16 & & & & & 15% \\ \hline \begin{tabular}{l} Blueberry \\ Muffin \end{tabular} & $1,011.05 & $1,640.95 & 0.62 & & & & & 5% \\ \hline \begin{tabular}{l} Total \\ Sales \end{tabular} & $28,478.61 & $30,946.34 & & & & & & 100% \\ \hline \end{tabular}