depend vs revolve around

depend

verb
  • To trust; to have confidence; to rely. 

  • To hang down; to be sustained by being fastened or attached to something above. 

  • To cause to be contingent or dependent on; to set as a necessity. 

  • To be contingent or conditioned; to have something as a necessary condition; to hinge on. 

revolve around

verb
  • To be connected with; to concern. 

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