Source: U.S. Bureau of Labor Statistics
The BLS defines marginally attached workers as persons who are not in the labor force, want and are available for work, and had looked for a job sometime in the prior 12 months. They are not counted as unemployed because they had not searched for work in the prior 4 weeks, for any reason whatsoever. The marginally attached are a group that includes discouraged workers.
U.S. Bureau of Labor Statistics, All Marginally Attached Workers for the District of Columbia [ALLMARGATDC], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/ALLMARGATDC, September 20, 2019.