rest home vs sanctum sanctorum

rest home

noun
  • A place of residence for people who require constant nursing care and have significant deficiencies with activities of daily living, such as the elderly and younger adults with physical disabilities. 

sanctum sanctorum

noun
  • A person's most private retreat or sanctuary. 

  • The Holy of Holies in the Jewish temple. 

How often have the words rest home and sanctum sanctorum occurred in a corpus of books? (source: Google Ngram Viewer )