Participation in traditional pension plans dropped to a new low in 2005, while the number of such plans declined sharply, the Employee Benefits Research Institute reports.

EBRI, Washington, says 16 million active private-sector workers were covered by traditional single-employer defined-benefit plans in 2005, down from 22% from the total in 1988.

The number of single-employer plans, which are typically nonunion plans, fell 74% between 1985 and 2005, to 28,769.

The fall was most severe among small and midsize employers, EBRI says. Most single-employer defined-benefit pension that remain are at large employers.

Including retirees, the Pension Benefit Guaranty Corp., Washington, insures the pensions of over 44 million private-sector defined-benefit plan participants, EBRI reports.