instead vs otherwise

instead

adv
  • In the place of something (usually mentioned earlier); as a substitute or alternative. 

otherwise

adv
  • Differently, in another way. 

  • In different circumstances; or else. 

  • In all other respects. 

adj
  • Other than supposed; different. 

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