Final answer:
The largest component of total income in the US includes personal income taxes and payroll taxes. Corporate income tax accounts for about 9% of federal tax revenue and has declined as a proportion of GDP over time.
Step-by-step explanation:
The largest component of total income in the United States is not the net foreign factor, but rather personal income taxes and payroll taxes, which together constitute the main sources of federal revenue. Compensation of employees is also a significant contributor to total income. Although corporate profits are considerable, the corporate income tax represents the third-largest source of federal tax revenue, contributing around 9 percent as of the fiscal year 2010. It is worth noting that over time, corporate income tax receipts have declined as a share of GDP, from about 4% in the 1960s to an average of 1% to 2% of GDP in recent decades.