Billions of Dollars Not Seasonally Adjusted, The series is calculated by the Federal Reserve Bank of St.Louis. Prior to 2003-01-01, the data are calculated as excess reserves minus total borrowings plus extended borrowings. From 2003-01-01 till 2007-11-01, the observations reflect excess reserves minus total borrowings plus secondary borrowings. From 2007-12-01, the definition changes to excess reserves minus discount window borrowings plus secondary borrowings. Please, check the latest definition of the discount window borrowings at http://research.stlouisfed.org/fred2/series/DISCBORR. This series has been discontinued with a phase of the simplification of reserves administration (http://www.frbservices.org/centralbank/reservescentral/reserves_administration_resource_center.html).