Comparative Statements for Warmer Corporation Are Shown Below $\quad$ $\quad$

Comparative statements for Warmer Corporation are shown below:
$\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$$\text {Warmer Corporation}$
$\quad$ $\quad$ $\quad$ $\quad$ $\quad$$\text {Comparative Income Statements}$
$\quad$ $\quad$ $\quad$ $\quad$ $\quad$$\text {For the years ended December 31}$
$\begin{array}{|l|r|r|r|}\hline \text { Sales } & {2018} & {2017} &{2016} \\\hline \text { Cost of goods sold } & \$ 14,800 & \$ 13,229 & \$ 13,994 \\\hline \text { Gross profit } & 8,224 & 8,661 & 8,375 \\\hline \text { Operating expenses } & 6,571 & 4,568 & 5,619 \\\hline \text { Operating income } & 3,664 & 3,576 & 3,487 \\\hline\end{array}$ Calculate trend percentages for all income statement amounts shown and comment on the results. Use 2016 as the base year. Comment on the results.