Here is an interesting chart about the labor force participation rate which appears to have improved somewhat over its low point in late '15. The decline relative to '07 appears to be increasingly attributable to the baby boomers aging out of the workforce. The "Cyclical" category subsumes "discouraged" workers and that number appears to be nearly non-existent at this point. "Other" includes students, disability, stay-at-home parents, etc. Surely there's some overlap between "Other" and "Aging" as retirement ages increase and elder workers have on-the-job injuries.