what's the gross margin?

Table 2 Income Statements	2018	2019	2020	2021
Sales	$3,346,750	$3,380,550	$3,635,000	$4,240,000
Cost of goods sold	$2,510,063	$2,384,000	$2,980,000	$3,680,000
Operating expenses:
Depreciation	$105,000	$105,000	$154,500	$159,000
Selling & Administrative Expense	$484,288	$404,300	$297,550	$303,320
Operating Income	$247,400	$487,250	$202,950	$97,680
Interest Expense	$0	$0	$43,000	$67,000
Pre-tax Profit	$247,400	$487,250	$159,950	$30,680
Income Tax Expense (Benefit)	$98,960	$194,900	$63,980	$12,272
Net Income	$148,440	$292,350	$95,970	$18,408