These Figures Represent The Number Of Persons Unemployed 15 Weeks And Over As A Per Cent Of The Total Civilian Labor Force. Beginning In 1960, Data Include Alaska And Hawaii. Population Data From The 1960 Census Were Introduced In April 1962. This Resulted In A Slight Reduction In Labor Force Totals, But None In The Estimates Of Unemployment. Population Data From The 1950 Census Were Used Prior To April 1962. Source: Bureau Of Labor Statistics, Monthly Report On The Labor Force, March, 1969, P. 161, For 1948-1968 Data, And Subsequent Issues Of Monthly Report On The Labor Force Thereafter. This NBER data series m08320 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html. NBER Indicator: m08320