Beginning 2010Q1: Level from Freddie Mac 10-K or 10-Q, table Freddie Mac Mortgage-Related Securities (previously titled PCs and Structured Securities), column Issued by Non-Consolidated Trusts, sum of rows Multifamily and Other Guarantee Transactions: All Other Guarantee Transactions: Multifamily. Unadjusted flow is the change in the level; data for the most recent ten years show no significant seasonality. Prior to 2010Q1: Level from Freddie Mac, annual and quarterly reports, table Issued Guaranteed PC's and Structured Securities, Total multifamily. Unadjusted flow is the change in the level; data for the most recent ten years show no significant seasonality.