endangered vs usual

endangered

adj
  • in danger, at risk, said of something where there is a strong possibility something bad will happen to it (for example, a species in danger of going extinct) 

usual

noun
  • A specific good or service (e.g. a drink) that someone typically orders. 

  • The typical state of something, or something that is typical. 

adj
  • Most commonly occurring; typical. 

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