Data Through June 1961 Are Based On 25 Year Mortgages Prepaid In 12 Years; Data For July 1961-1965 Are Based On 30 Year Mortgages Prepaid In 15 Years. Source: U.S. Department Of Commerce, Business Condition Digest.
This NBER data series m13045 appears on the NBER website in Chapter 13 at http://www.nber.org/databases/macrohistory/contents/chapter13.html.
NBER Indicator: m13045
Release: NBER Macrohistory Database
National Bureau of Economic Research, Secondary Market Yields On Federal Housing Administration Mortgages for United States [M13045USM156NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M13045USM156NNBR/, October 4, 2015.