In 1841, the householder was told to:
"Write in figures the age of every person, opposite to their names, in one of the columns headed "Age of Males" or "Age of Females" according to their sex. For persons aged 15 years and upwards it is sufficient to state within what period of five years their age is, writing down the lowest number of that period: thus, for persons aged 15 and under 20, write 15- for 20 and under 25, write 20- for 25 and under 30, write 25- for 30 and under 35, write 30-, and so on up to the greatest age; but the exact age may be stated if the person prefers it. For persons under 15, write the number of years; for infants under one year, the number of months."
Whether your average ag lab householder would have known what to make of this seems highly questionable!
David.-