point one...to make sure you are the only one using that number.
point two I can think of right off is...to make sure to have a number.
I could probably come up with a few more, if your really that interested.
I am. Since the only information they need is the number of people in a house, to determine how many Representatives your district needs, it's irrelvant what their name is, what sex they are or anything else.
If I say 3, they don't need to know my name or my wifes name or my kids name 7 tehy damn sure don't need to give me a number to answer the questions.