charwoman vs houseboy

charwoman

noun
  • A woman employed to do housework, traditionally coming and going on a daily basis and paid weekly wages. 

houseboy

noun
  • A non-white adult male domestic servant. 

  • A young male domestic servant, especially in a British colony in former times. 

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