Vertical analysis $($common$-$size$)$ percentages for Austin Company$$s sales, cost of goods sold, and expenses are listed here.

Vertical Analysis $202320222021$

Sales revenue $100\mathrm{.}0\%100\mathrm{.}0\%100\mathrm{.}0\%$

Cost of goods sold $61\mathrm{.}262\mathrm{.}463\mathrm{.}5$

Operating expenses $26\mathrm{.}527\mathrm{.}428\mathrm{.}5$

Did Austin Company$$s net income as a percent of sales increase, decrease, or remain unchanged over the $3-$year period? Provide numerical support for your answer?