Sure. That figure's from policy analyst Matt Bruenig, and the data source was the Annual Social and Economic Supplement (ASEC) of the Current Population Survey (CPS). He breaks down how many people belong to each category pretty well in this post:

https://www.peoplespolicyproject.org/2018/09/18/the-best-way-to-eradicate-poverty-welfare-not-jobs/

By definition, these are people who earn zero market income in a given year, so they have done no market labor whatsoever.