mainstay vs satisfactory

mainstay

noun
  • Someone or something that can be depended on to make a regular contribution. 

  • A stabilising rope from the top of the mainmast to the bottom of the foremast. 

  • A chief support. 

satisfactory

noun
  • Somebody or something that meets requirements without exceeding them. 

  • The rating given to somebody or something that meets requirements without exceeding them. 

adj
  • Causing satisfaction; agreeable or pleasant; satisfying. 

  • Done to satisfaction; adequate or sufficient. 

  • Making atonement for a sin; expiatory. 

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