cloak vs sweep under the carpet

cloak

noun
  • A long outer garment worn over the shoulders covering the back; a cape, often with a hood. 

  • That which conceals; a disguise or pretext. 

  • A blanket-like covering, often metaphorical. 

  • A text replacement for an IRC user's hostname or IP address, making the user less identifiable. 

verb
  • To cover up, hide or conceal. 

  • To render or become invisible via futuristic technology. 

  • To cover as with a cloak. 

sweep under the carpet

How often have the words cloak and sweep under the carpet occurred in a corpus of books? (source: Google Ngram Viewer )