instable vs staggering

instable

adj
  • Exhibiting instability; unstable 

staggering

adj
  • Lurching, floundering. 

  • Incredible, overwhelming, amazing. 

noun
  • The motion of one who staggers. 

  • The condition of being staggered or amazed. 

  • In animation, the repetition of a sequence of frames to show struggling effort 

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