Year-end level from financial statements compiled by and purchased from SNL Financial. Staff tabulation of U.S. Treasury securities from Annual and Separate Account Statements, Schedule D, book value; plus from the Annual Statement, table Assets, a portion of line 5, Short-term investments and from the Separate Accounts Statement, a portion of line 7, Short-term investments. Levels for other quarters estimated from staff tabulation of quarterly statement, table Assets, percentage of line 1, Bonds, plus FOF Section estimate of U.S. Treasury securities held in Separate Accounts. Percentage used is FOF Section estimate based on distribution of annual bond data. Unadjusted flow is the change in the level; data for the most recent ten years show no significant seasonality.