The SOI Individual Complete Report sample is a probability sample of unaudited Individual Income Tax Returns (Form 1040 and 1040-SR (including electronic returns)) filed by U.S. citizens and residents during a Calendar Year. The sample is drawn to estimate the entire population of US Individual taxpayers for a given calendar year. The annual sample contains approximately 360,000 returns comprised of a possible 4,000 data items extracted from over 70 forms and schedules.