Given below are selected financial data from the Coca-Cola Company's income statement and balance sheet for the years 2019, 2020, and 2021. Use this information to answer the following questions:

	2019	2020	2021
Sales	$40,000	$35,000	$38,000
Cost of Goods Sold	$15,000	$13,000	$14,500
Gross Profit	$25,000	$22,000	$23,500
Selling Expenses	$10,000	$8,000	$9,000
Administrative Expenses	$5,000	$5,500	$5,200
Net Income	$8,000	$6,000	$7,300

	2019	2020	2021
Total Assets	$100,000	$95,000	$98,000
Total Liabilities	$60,000	$55,000	$57,000
Shareholders' Equity	$40,000	$40,000	$41,000

Requirements:

1. Calculate the gross profit margin for each year.
2. Determine the net profit margin for each year.
3. Calculate the return on assets (ROA) for each year.
4. Compute the return on equity (ROE) for each year.
5. Analyze the trend in the company's profitability and provide a brief explanation.