adhere vs co-occur

adhere

verb
  • To stick fast or cleave, as a glutinous substance does; to become joined or united. 

  • To affirm a judgment. 

  • To be attached or devoted by personal union, in belief, on principle, etc. 

  • To be consistent or coherent; to be in accordance; to agree. 

co-occur

verb
  • To occur together. 

How often have the words adhere and co-occur occurred in a corpus of books? (source: Google Ngram Viewer )