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

Not included in Adjusted Gross Income (AGI). Represents interest on State and local government obligations, including tax-exempt interest dividends from a mutual fund or other regulated investment companies.

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.