Year-end level estimated from DOL, Employee Benefits Security Administration, Private Pension Plan Bulletin: Abstract of Form 5500 Annual Reports, Table C4. Balance Sheet of Pension Plans with 100 or More Participants, Defined Benefit, as the sum of Assets in pooled separate accounts and Assets in insurance company general accounts, adjusted for plans whose fiscal years do not end on December 31 and to include plans with fewer than 100 participants. Data are available with a two-year lag. Series is converted to quarterly and estimated for quarters after last benchmark using data from a sample of plans available by subscription from State Street Analytics and the Independent Consultants Cooperative. The unadjusted flow is the change in the level less estimated capital gains; data for the most recent ten years show no significant seasonality.