foster care vs upbringing

foster care

noun
  • A formal system by which a child is cared for, in a foster family, by people other than its own parents, but without being adopted. 

upbringing

noun
  • The raising or training of a child. 

  • The traits acquired during one's childhood training 

How often have the words foster care and upbringing occurred in a corpus of books? (source: Google Ngram Viewer )