Obtain each person's age in completed years, that is, his/her age at his/her last birthday. If you have difficulty obtaining the ages of very elderly members of the household, you may enter the code 99, meaning "doesn't know" or "over age 50". If a child has not yet reached his/her first birthday, write 00: for example, a child who is 9 months old is coded as 00. If necessary, a more accurate estimate of the child's age will be obtained later in the questionnaire. You must record an age for each child. Do not leave this item blank for any child.