How do I calculate the Net Profit Margin for this? (Amounts in millions, except per share data)						2020	2019	2018
Revenues:
	Net sales					$ 519,926	$ 510,329	$ 495,761
	Membership and other income					4,038	4,076	4,582
		Total revenues				$ 523,964	$ 514,405	$ 500,343
Costs and expenses:
	Cost of sales					$ 394,605	$ 385,301	$ 373,396
	Operating, selling, general and administrative expenses					108,791	107,147	106,510
Operating income						20,568	21,957	20,437
Interest:
	Debt					2,262	1,975	1,978
	Finance, capital lease and financing obligations					337	371	352
	Interest income					(189)	(217)	(152)
		Interest, net				2,410	2,129	2,178
Loss on extinguishment of debt						-	-	3,316
Other (gains) and losses						(1,958)	8,368	-
Income before income taxes						20,116	11,460	15,123
Provision for income taxes						4,915	4,281	4,600
Consolidated net income						15,201	7,179	10,523
Consolidated net income attributable to noncontrolling interest						(320)	(509)	(661)
Consolidated net income attributable to Walmart						14,881	6,670	9,862