Tech Innovators Inc. presents its financial statements for the years ended December 31, 2021, 2020, and 2019.

Description	2021	2020	2019
Revenue	$5,000,000	$4,000,000	$3,500,000
Cost of Revenue	$3,000,000	$2,400,000	$2,100,000
Gross Profit	$2,000,000	$1,600,000	$1,400,000
Research and Development	$600,000	$480,000	$420,000
Selling, General, and Admin	$800,000	$640,000	$560,000
Operating Income	$600,000	$480,000	$420,000
Other Income	$100,000	$80,000	$70,000
Earnings Before Tax	$700,000	$560,000	$490,000
Tax Expense	$140,000	$112,000	$98,000
Net Income	$560,000	$448,000	$392,000

Requirements:

1. Create a common-size income statement for each year.
2. Calculate the R&D Expense Ratio for each year.
3. Determine the SG&A Expense Ratio for each year.
4. Evaluate the company's investment in R&D over the three years.