The latest IRS Statistics of Income Bulletin (Publication 1304 (Rev. 11-2022) (irs.gov)) show that 164.4 million individual income tax returns were filed for 2020, or 4.2% more than in the previous tax year. Only 9.5% of all returns filed claimed itemized deductions; the vast majority used the applicable standard deduction amount.
The 2020 return reflected various COVID-19 related tax changes enacted by the CARES Act of 2020 and the American Rescue Plan Act of 2021, including:
Tax paid by self-employed persons to finance Social Security coverage. In 2007, there are two rates. A 12.4% rate applies to a taxable earnings base of $95,700 or less and a 2.9% rate applies to all net earnings.