I have never entered by birthday into facebook, or told it where I work, what I do, my relationship status or where and when I was educated.
Which, going by the number of times it keeps "reminding" me about this obviously annoys facebook's data trawling robot a great deal. Probably because it reduces the financial value to advertisers of the trawled data to whoever facebook wants to sell targeted advertising space to.
Which is one reason why I never entered those details in the first place.