Column 7 and 8: Date of birth:
Mark the month of birth in numbers in column 7 and the year of birth in numbers in the column 8.
[Month numbers and examples omitted]
If someone doesn't know their month of birth, mark a line in column 7 and mark their year of birth in column 8.
If someone doesn't know either their month of birth or their year of birth, mark a line in column 7 and 8 and go on to column 9