Analyze the financial data of AT&T Inc. for the years 2018, 2019, and 2020 provided below:

	2018	2019	2020
Revenue	$170,756	$181,193	$171,760
Cost of Revenue	$97,670	$103,456	$97,486
Gross Profit	$73,086	$77,737	$74,274
Operating Expenses	$51,998	$56,736	$52,616
Operating Income	$21,088	$21,001	$21,658
Net Income	$19,370	$14,975	$11,856

	2018	2019	2020
Total Assets	$517,727	$551,669	$551,365
Total Liabilities	$332,966	$344,399	$355,331
Shareholders' Equity	$184,761	$207,270	$196,034

Requirements:

1. Calculate the gross profit margin for each year.
2. Determine the operating profit margin for each year.
3. Calculate the net profit margin for each year.
4. Compute the return on assets (ROA) for each year.
5. Compute the return on equity (ROE) for each year.
6. Discuss the financial performance trend of AT&T Inc.