foster care vs fostering

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. 

fostering

noun
  • raising someone to be an accepted member of the community. 

  • encouragement; aiding the development of something 

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