babysitter vs childminder

babysitter

noun
  • A person who cares for one or more babies or children for a short period of time in place of their legal guardians. 

childminder

noun
  • A person employed to look after other people's children while they are away; a babysitter. 

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