Source: U.S. Department of the Treasury. Internal Revenue Service  

Release: SOI Tax Stats - Historical Data Tables  

Units:  Number of Returns, Not Seasonally Adjusted

Frequency:  Annual

Excludes certain royalties included in the computations of capital gain or loss and of ordinary gain or loss in sales of noncapital assets.

For additional information about the return filing requirements, see the annual reports, Statistics of Income-Individual Income Tax Returns at https://www.irs.gov/uac/soi-tax-stats-historical-data-tables.