Series is zero beginning 1994:Q1. Prior to 1993:Q4, level from Monthly Treasury Statement, table 6, schedule C (Memorandum), Borrowing from the Federal Financing Bank, Department of Education: Student Loan Marketing Association. In 2004:Q4, Sallie Mae was fully privatized and was moved to the finance company sector. Unadjusted flow is the change in the level; data for the most recent ten years show no significant seasonality.