Based on the unweighted average of the bid yields for all Treasury fixed-coupon securities with remaining terms to maturity of 25 years and over. Averages of business days. **DISCONTINUED** For further information, please refer to http://www.federalreserve.gov/releases/h15/treas_long-term_rate_discontinuence.htm.
Release: H.15 Selected Interest Rates
Board of Governors of the Federal Reserve System (US), Treasury Long-Term Average (25 years and above) (DISCONTINUED SERIES) [WLTA], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/WLTA/, July 29, 2015.