The 1939 National Registration tabulated age and gender structure using a greatly simplified nine-way classification of ages. The introduction to the report states that this was to aid the enumerators who were doing much of the analysis before sending the completed forms to the Registrar General. Again to simplify the forms, people were asked to state their year of birth rather than their age. The fractions in the age bands occurred because "In consequence of these procedure restrictions, the number of groups iden...

tified ... is limited to nine in respect of each sex and being calendar year of birth groups, they do not correspond with integral years of age owing to the fact that the enumeration took place at the end of the third quarter of 1939." The data are for the civilian population only; at this date, the armed services were almost all male, and under 45. An estimated 1,010,000 were in the services in Great Britain, of whom 900,000 were in England and Wales.