Financial data for Pfizer Inc. for the years ended December 31, 2023, 2022, and 2021 are provided below.

Pfizer Inc. Comparative Income Statements	2023	2022	2021
Sales	$650,000,000	$620,000,000	$590,000,000
Cost of goods sold	$390,000,000	$372,000,000	$354,000,000
Gross profit	$260,000,000	$248,000,000	$236,000,000
Operating expenses	$130,000,000	$124,000,000	$118,000,000
Income from operations	$130,000,000	$124,000,000	$118,000,000
Interest expense	$13,000,000	$12,400,000	$11,800,000
Income before taxes	$117,000,000	$111,600,000	$106,200,000
Income tax expense	$35,100,000	$33,480,000	$31,860,000
Net income	$81,900,000	$78,120,000	$74,340,000

Pfizer Inc. Comparative Balance Sheets	2023	2022	2021
Assets
Current assets	$130,000,000	$125,000,000	$120,000,000
Long-term investments	$170,000,000	$160,000,000	$150,000,000
Property and equipment, net	$300,000,000	$280,000,000	$260,000,000
Total assets	$600,000,000	$565,000,000	$530,000,000
Liabilities and Equity
Current liabilities	$100,000,000	$95,000,000	$90,000,000
Long-term debt	$250,000,000	$230,000,000	$210,000,000
Common stock	$150,000,000	$150,000,000	$150,000,000
Retained earnings	$100,000,000	$90,000,000	$80,000,000
Total liabilities and equity	$600,000,000	$565,000,000	$530,000,000

Requirements:

1. Prepare common-size income statements for 2023, 2022, and 2021.
2. Prepare common-size balance sheets for 2023, 2022, and 2021.
3. Calculate Pfizer’s return on assets (ROA) and return on equity (ROE) for the three years.
4. Discuss the trend in Pfizer’s gross profit margin and operating profit margin.