The United States Treasury discontinued the auction of 52-week T-bills at the end of February, 2001. In anticipation of this cessation, Congress passed legislation to establish a new interest rate index that was readily available. Congress enacted the Omnibus Appropriation Act (PL 106-554) that contained, among its various provisions, amendments to the federal statutes dealing with the interest rate on federal judgments.
This revision took effect on all judgments entered on and after December 21, 2000. Only the rate that is applied to judgments has changed. All other computational procedures remain the same.
The applicable rate is listed under US Government Securities - Treasury Constant Maturities - 1 year. The specific rate is found under the column headed week ending MM/DD, where MM/DD is the month and week ending date, e.g., Jan 26 or Feb 2. This can be found at the following website: http://www.federalreserve.gov/releases/h15/current/
Prior interest rates can be found using the Data Download Program at: https://www.federalreserve.gov/datadownload/Choose.aspx?rel=H.15