This is the age group we treat as 'working age' although the definition has changed over time. Compulsory education to age 10 was established in some areas from 1870, and was gradually raised up to 16 by 1973. The male retirement age was standardised at 65 only in 1925.

Despite the large change in overall age structure, the proportion of working age has changed relatively little: it was smallest in 1871 and 1881 (59%), and at its greatest in 1931 (69%). The main concentrations of the workforce were in areas of rapid population growth, so in 1851 they were in the industrial districts and London. In 2011, low proportions of working age population are generally in rural areas, and also in coastal areas affected by retirement migration.